diff --git a/config/test.json b/config/test.json
index ade27eef3..fbec72db9 100644
--- a/config/test.json
+++ b/config/test.json
@@ -1,4 +1,4 @@
 {
   "storageProfile": "test",
-  "openDevTools": false
+  "openDevTools": true
 }
diff --git a/ts/ConversationController.ts b/ts/ConversationController.ts
index 56bc0a776..2b04e2581 100644
--- a/ts/ConversationController.ts
+++ b/ts/ConversationController.ts
@@ -13,17 +13,107 @@ import type {
 import type { ConversationModel } from './models/conversations';
 import { getContactId } from './messages/helpers';
 import { maybeDeriveGroupV2Id } from './groups';
-import { assert } from './util/assert';
+import { assert, strictAssert } from './util/assert';
 import { isGroupV1, isGroupV2 } from './util/whatTypeOfConversation';
 import { getConversationUnreadCountForAppBadge } from './util/getConversationUnreadCountForAppBadge';
-import { UUID, isValidUuid } from './types/UUID';
+import { UUID, isValidUuid, UUIDKind } from './types/UUID';
+import type { UUIDStringType } from './types/UUID';
 import { Address } from './types/Address';
 import { QualifiedAddress } from './types/QualifiedAddress';
 import * as log from './logging/log';
+import * as Errors from './types/errors';
 import { sleep } from './util/sleep';
 import { isNotNil } from './util/isNotNil';
 import { MINUTE, SECOND } from './util/durations';
 
+type ConvoMatchType =
+  | {
+      key: 'uuid' | 'pni';
+      value: UUIDStringType | undefined;
+      match: ConversationModel | undefined;
+    }
+  | {
+      key: 'e164';
+      value: string | undefined;
+      match: ConversationModel | undefined;
+    };
+
+const { hasOwnProperty } = Object.prototype;
+
+function applyChangeToConversation(
+  conversation: ConversationModel,
+  suggestedChange: Partial<
+    Pick<ConversationAttributesType, 'uuid' | 'e164' | 'pni'>
+  >
+) {
+  const change = { ...suggestedChange };
+
+  // Clear PNI if changing e164 without associated PNI
+  if (hasOwnProperty.call(change, 'e164') && !change.pni) {
+    change.pni = undefined;
+  }
+
+  // If we have a PNI but not an ACI, then the PNI will go in the UUID field
+  //   Tricky: We need a special check here, because the PNI can be in the uuid slot
+  if (
+    change.pni &&
+    !change.uuid &&
+    (!conversation.get('uuid') ||
+      conversation.get('uuid') === conversation.get('pni'))
+  ) {
+    change.uuid = change.pni;
+  }
+
+  // If we're clearing a PNI, but we didn't have an ACI - we need to clear UUID field
+  if (
+    !change.uuid &&
+    hasOwnProperty.call(change, 'pni') &&
+    !change.pni &&
+    conversation.get('uuid') === conversation.get('pni')
+  ) {
+    change.uuid = undefined;
+  }
+
+  if (hasOwnProperty.call(change, 'uuid')) {
+    conversation.updateUuid(change.uuid);
+  }
+  if (hasOwnProperty.call(change, 'e164')) {
+    conversation.updateE164(change.e164);
+  }
+  if (hasOwnProperty.call(change, 'pni')) {
+    conversation.updatePni(change.pni);
+  }
+
+  // Note: we don't do a conversation.set here, because change is limited to these fields
+}
+
+async function mergeConversations({
+  logId,
+  oldConversation,
+  newConversation,
+}: {
+  logId: string;
+  oldConversation: ConversationModel;
+  newConversation: ConversationModel;
+}) {
+  try {
+    await window.ConversationController.combineConversations(
+      newConversation,
+      oldConversation
+    );
+
+    // If the old conversation was currently displayed, we load the new one
+    window.Whisper.events.trigger('refreshConversation', {
+      newId: newConversation.get('id'),
+      oldId: oldConversation.get('id'),
+    });
+  } catch (error) {
+    log.warn(
+      `${logId}: error combining contacts: ${Errors.toLogFormat(error)}`
+    );
+  }
+}
+
 const MAX_MESSAGE_BODY_LENGTH = 64 * 1024;
 
 const {
@@ -55,6 +145,8 @@ export class ConversationController {
 
   private _hasQueueEmptied = false;
 
+  private _combineConversationsQueue = new PQueue({ concurrency: 1 });
+
   constructor(private _conversations: ConversationModelCollectionType) {
     const debouncedUpdateUnreadCount = debounce(
       this.updateUnreadCount.bind(this),
@@ -172,8 +264,8 @@ export class ConversationController {
     if (type === 'group') {
       conversation = this._conversations.add({
         id,
-        uuid: null,
-        e164: null,
+        uuid: undefined,
+        e164: undefined,
         groupId: identifier,
         type,
         version: 2,
@@ -183,8 +275,8 @@ export class ConversationController {
       conversation = this._conversations.add({
         id,
         uuid: identifier,
-        e164: null,
-        groupId: null,
+        e164: undefined,
+        groupId: undefined,
         type,
         version: 2,
         ...additionalInitialProps,
@@ -192,9 +284,9 @@ export class ConversationController {
     } else {
       conversation = this._conversations.add({
         id,
-        uuid: null,
+        uuid: undefined,
         e164: identifier,
-        groupId: null,
+        groupId: undefined,
         type,
         version: 2,
         ...additionalInitialProps,
@@ -270,13 +362,25 @@ export class ConversationController {
 
   getOurConversationId(): string | undefined {
     const e164 = window.textsecure.storage.user.getNumber();
-    const uuid = window.textsecure.storage.user.getUuid()?.toString();
-    return this.ensureContactIds({
+    const aci = window.textsecure.storage.user
+      .getUuid(UUIDKind.ACI)
+      ?.toString();
+    const pni = window.textsecure.storage.user
+      .getUuid(UUIDKind.PNI)
+      ?.toString();
+
+    if (!e164 && !aci && !pni) {
+      return undefined;
+    }
+
+    const conversation = this.maybeMergeContacts({
+      aci,
       e164,
-      uuid,
-      highTrust: true,
+      pni,
       reason: 'getOurConversationId',
     });
+
+    return conversation?.id;
   }
 
   getOurConversationIdOrThrow(): string {
@@ -311,39 +415,210 @@ export class ConversationController {
     return ourDeviceId === 1;
   }
 
+  // Note: If you don't know what kind of UUID it is, put it in the 'aci' param.
+  maybeMergeContacts({
+    aci: providedAci,
+    e164,
+    pni: providedPni,
+    reason,
+    mergeOldAndNew = mergeConversations,
+  }: {
+    aci?: string;
+    e164?: string;
+    pni?: string;
+    reason: string;
+    recursionCount?: number;
+    mergeOldAndNew?: (options: {
+      logId: string;
+      oldConversation: ConversationModel;
+      newConversation: ConversationModel;
+    }) => Promise<void>;
+  }): ConversationModel | undefined {
+    const dataProvided = [];
+    if (providedAci) {
+      dataProvided.push('aci');
+    }
+    if (e164) {
+      dataProvided.push('e164');
+    }
+    if (providedPni) {
+      dataProvided.push('pni');
+    }
+    const logId = `maybeMergeContacts/${reason}/${dataProvided.join('+')}`;
+
+    const aci = providedAci ? UUID.cast(providedAci) : undefined;
+    const pni = providedPni ? UUID.cast(providedPni) : undefined;
+
+    if (!aci && !e164 && !pni) {
+      throw new Error(
+        `${logId}: Need to provide at least one of: aci, e164, pni`
+      );
+    }
+
+    if (pni && !e164) {
+      throw new Error(`${logId}: Cannot provide pni without an e164`);
+    }
+
+    const identifier = aci || e164 || pni;
+    strictAssert(identifier, `${logId}: identifier must be truthy!`);
+
+    const matches: Array<ConvoMatchType> = [
+      {
+        key: 'uuid',
+        value: aci,
+        match: window.ConversationController.get(aci),
+      },
+      {
+        key: 'e164',
+        value: e164,
+        match: window.ConversationController.get(e164),
+      },
+      { key: 'pni', value: pni, match: window.ConversationController.get(pni) },
+    ];
+    let unusedMatches: Array<ConvoMatchType> = [];
+
+    let targetConversation: ConversationModel | undefined;
+    let matchCount = 0;
+    matches.forEach(item => {
+      const { key, value, match } = item;
+
+      if (!value) {
+        return;
+      }
+
+      if (!match) {
+        if (targetConversation) {
+          log.info(
+            `${logId}: No match for ${key}, applying to target conversation`
+          );
+          // Note: This line might erase a known e164 or PNI
+          applyChangeToConversation(targetConversation, {
+            [key]: value,
+          });
+        } else {
+          unusedMatches.push(item);
+        }
+        return;
+      }
+
+      matchCount += 1;
+      unusedMatches.forEach(unused => {
+        strictAssert(unused.value, 'An unused value should always be truthy');
+
+        // Example: If we find that our PNI match has no ACI, then it will be our target.
+        //   Tricky: PNI can end up in UUID slot, so we need to special-case it
+        if (
+          !targetConversation &&
+          (!match.get(unused.key) ||
+            (unused.key === 'uuid' && match.get(unused.key) === pni))
+        ) {
+          log.info(
+            `${logId}: Match on ${key} does not have ${unused.key}, ` +
+              `so it will be our target conversation - ${match.idForLogging()}`
+          );
+          targetConversation = match;
+        }
+
+        // If PNI match already has an ACI, then we need to create a new one
+        if (!targetConversation) {
+          targetConversation = this.getOrCreate(unused.value, 'private');
+          log.info(
+            `${logId}: Match on ${key} already had ${unused.key}, ` +
+              `so created new target conversation - ${targetConversation.idForLogging()}`
+          );
+        }
+
+        log.info(
+          `${logId}: Applying new value for ${unused.key} to target conversation`
+        );
+        applyChangeToConversation(targetConversation, {
+          [unused.key]: unused.value,
+        });
+      });
+
+      unusedMatches = [];
+
+      if (targetConversation && targetConversation !== match) {
+        // Clear the value on the current match, since it belongs on targetConversation!
+        //   Note: we need to do the remove first, because it will clear the lookup!
+        log.info(
+          `${logId}: Clearing ${key} on match, and adding it to target conversation`
+        );
+        const change: Pick<
+          Partial<ConversationAttributesType>,
+          'uuid' | 'e164' | 'pni'
+        > = {
+          [key]: undefined,
+        };
+        // When the PNI is being used in the uuid field alone, we need to clear it
+        if (key === 'pni' && match.get('uuid') === pni) {
+          change.uuid = undefined;
+        }
+        applyChangeToConversation(match, change);
+
+        applyChangeToConversation(targetConversation, {
+          [key]: value,
+        });
+
+        // Note: The PNI check here is just to be bulletproof; if we know a UUID is a PNI,
+        //   then that should be put in the UUID field as well!
+        if (!match.get('uuid') && !match.get('e164') && !match.get('pni')) {
+          log.warn(
+            `${logId}: Removing old conversation which matched on ${key}. ` +
+              'Merging with target conversation.'
+          );
+          mergeOldAndNew({
+            logId,
+            oldConversation: match,
+            newConversation: targetConversation,
+          });
+        }
+      } else if (targetConversation && !targetConversation?.get(key)) {
+        // This is mostly for the situation where PNI was erased when updating e164
+        // log.debug(`${logId}: Re-adding ${key} on target conversation`);
+        applyChangeToConversation(targetConversation, {
+          [key]: value,
+        });
+      }
+
+      if (!targetConversation) {
+        // log.debug(
+        //   `${logId}: Match on ${key} is target conversation - ${match.idForLogging()}`
+        // );
+        targetConversation = match;
+      }
+    });
+
+    if (targetConversation) {
+      return targetConversation;
+    }
+
+    strictAssert(
+      matchCount === 0,
+      `${logId}: should be no matches if no targetConversation`
+    );
+
+    log.info(`${logId}: Creating a new conversation with all inputs`);
+    return this.getOrCreate(identifier, 'private', { e164, pni });
+  }
+
   /**
-   * Given a UUID and/or an E164, resolves to a string representing the local
-   * database id of the given contact. In high trust mode, it may create new contacts,
-   * and it may merge contacts.
-   *
-   * highTrust = uuid/e164 pairing came from CDS, the server, or your own device
+   * Given a UUID and/or an E164, returns a string representing the local
+   * database id of the given contact. Will create a new conversation if none exists;
+   * otherwise will return whatever is found.
    */
-  ensureContactIds({
+  lookupOrCreate({
     e164,
     uuid,
-    highTrust,
-    reason,
-  }:
-    | {
-        e164?: string | null;
-        uuid?: string | null;
-        highTrust?: false;
-        reason?: void;
-      }
-    | {
-        e164?: string | null;
-        uuid?: string | null;
-        highTrust: true;
-        reason: string;
-      }): string | undefined {
-    // Check for at least one parameter being provided. This is necessary
-    // because this path can be called on startup to resolve our own ID before
-    // our phone number or UUID are known. The existing behavior in these
-    // cases can handle a returned `undefined` id, so we do that.
+  }: {
+    e164?: string | null;
+    uuid?: string | null;
+  }): ConversationModel | undefined {
     const normalizedUuid = uuid ? uuid.toLowerCase() : undefined;
     const identifier = normalizedUuid || e164;
 
     if ((!e164 && !uuid) || !identifier) {
+      log.warn('lookupOrCreate: Called with neither e164 nor uuid!');
       return undefined;
     }
 
@@ -352,147 +627,52 @@ export class ConversationController {
 
     // 1. Handle no match at all
     if (!convoE164 && !convoUuid) {
-      log.info(
-        'ensureContactIds: Creating new contact, no matches found',
-        highTrust ? reason : 'no reason'
-      );
+      log.info('lookupOrCreate: Creating new contact, no matches found');
       const newConvo = this.getOrCreate(identifier, 'private');
-      if (highTrust && e164) {
+
+      // `identifier` would resolve to uuid if we had both, so fix up e164
+      if (normalizedUuid && e164) {
         newConvo.updateE164(e164);
       }
-      if (normalizedUuid) {
-        newConvo.updateUuid(normalizedUuid);
-      }
-      if ((highTrust && e164) || normalizedUuid) {
-        updateConversation(newConvo.attributes);
-      }
 
-      return newConvo.get('id');
-
-      // 2. Handle match on only E164
+      return newConvo;
     }
-    if (convoE164 && !convoUuid) {
-      const haveUuid = Boolean(normalizedUuid);
-      log.info(
-        `ensureContactIds: e164-only match found (have UUID: ${haveUuid})`
-      );
-      // If we are only searching based on e164 anyway, then return the first result
-      if (!normalizedUuid) {
-        return convoE164.get('id');
-      }
 
-      // Fill in the UUID for an e164-only contact
-      if (normalizedUuid && !convoE164.get('uuid')) {
-        if (highTrust) {
-          log.info(
-            `ensureContactIds: Adding UUID (${uuid}) to e164-only match ` +
-              `(${e164}), reason: ${reason}`
-          );
-          convoE164.updateUuid(normalizedUuid);
-          updateConversation(convoE164.attributes);
-        }
-        return convoE164.get('id');
-      }
-
-      log.info(
-        'ensureContactIds: e164 already had UUID, creating a new contact'
-      );
-      // If existing e164 match already has UUID, create a new contact...
-      const newConvo = this.getOrCreate(normalizedUuid, 'private');
-
-      if (highTrust) {
-        log.info(
-          `ensureContactIds: Moving e164 (${e164}) from old contact ` +
-            `(${convoE164.get('uuid')}) to new (${uuid}), reason: ${reason}`
-        );
-
-        // Remove the e164 from the old contact...
-        convoE164.set({ e164: undefined });
-        updateConversation(convoE164.attributes);
-
-        // ...and add it to the new one.
-        newConvo.updateE164(e164);
-        updateConversation(newConvo.attributes);
-      }
-
-      return newConvo.get('id');
-
-      // 3. Handle match on only UUID
-    }
+    // 2. Handle match on only UUID
     if (!convoE164 && convoUuid) {
-      if (e164 && highTrust) {
-        log.info(
-          `ensureContactIds: Adding e164 (${e164}) to UUID-only match ` +
-            `(${uuid}), reason: ${reason}`
-        );
-        convoUuid.updateE164(e164);
-        updateConversation(convoUuid.attributes);
-      }
-      return convoUuid.get('id');
+      return convoUuid;
+    }
+
+    // 3. Handle match on only E164
+    if (convoE164 && !convoUuid) {
+      return convoE164;
     }
 
     // For some reason, TypeScript doesn't believe that we can trust that these two values
-    //   are truthy by this point. So we'll throw if we get there.
+    //   are truthy by this point. So we'll throw if that isn't the case.
     if (!convoE164 || !convoUuid) {
-      throw new Error('ensureContactIds: convoE164 or convoUuid are falsey!');
-    }
-
-    // Now, we know that we have a match for both e164 and uuid checks
-
-    if (convoE164 === convoUuid) {
-      return convoUuid.get('id');
-    }
-
-    if (highTrust) {
-      // Conflict: If e164 match already has a UUID, we remove its e164.
-      if (convoE164.get('uuid') && convoE164.get('uuid') !== normalizedUuid) {
-        log.info(
-          `ensureContactIds: e164 match (${e164}) had different ` +
-            `UUID(${convoE164.get('uuid')}) than incoming pair (${uuid}), ` +
-            `removing its e164, reason: ${reason}`
-        );
-
-        // Remove the e164 from the old contact...
-        convoE164.set({ e164: undefined });
-        updateConversation(convoE164.attributes);
-
-        // ...and add it to the new one.
-        convoUuid.updateE164(e164);
-        updateConversation(convoUuid.attributes);
-
-        return convoUuid.get('id');
-      }
-
-      log.warn(
-        `ensureContactIds: Found a split contact - UUID ${normalizedUuid} and E164 ${e164}. Merging.`
+      throw new Error(
+        'lookupOrCreate: convoE164 or convoUuid are falsey but should both be true!'
       );
-
-      // Conflict: If e164 match has no UUID, we merge. We prefer the UUID match.
-      // Note: no await here, we want to keep this function synchronous
-      convoUuid.updateE164(e164);
-      // `then` is used to trigger async updates, not affecting return value
-      // eslint-disable-next-line more/no-then
-      this.combineConversations(convoUuid, convoE164)
-        .then(() => {
-          // If the old conversation was currently displayed, we load the new one
-          window.Whisper.events.trigger('refreshConversation', {
-            newId: convoUuid.get('id'),
-            oldId: convoE164.get('id'),
-          });
-        })
-        .catch(error => {
-          const errorText = error && error.stack ? error.stack : error;
-          log.warn(`ensureContactIds error combining contacts: ${errorText}`);
-        });
     }
 
-    return convoUuid.get('id');
+    // 4. If the two lookups agree, return that conversation
+    if (convoE164 === convoUuid) {
+      return convoUuid;
+    }
+
+    // 5. If the two lookups disagree, log and return the UUID match
+    log.warn(
+      `lookupOrCreate: Found a split contact - UUID ${normalizedUuid} and E164 ${e164}. Returning UUID match.`
+    );
+    return convoUuid;
   }
 
   async checkForConflicts(): Promise<void> {
     log.info('checkForConflicts: starting...');
     const byUuid = Object.create(null);
     const byE164 = Object.create(null);
+    const byPni = Object.create(null);
     const byGroupV2Id = Object.create(null);
     // We also want to find duplicate GV1 IDs. You might expect to see a "byGroupV1Id" map
     //   here. Instead, we check for duplicates on the derived GV2 ID.
@@ -509,6 +689,7 @@ export class ConversationController {
       );
 
       const uuid = conversation.get('uuid');
+      const pni = conversation.get('pni');
       const e164 = conversation.get('e164');
 
       if (uuid) {
@@ -532,6 +713,27 @@ export class ConversationController {
         }
       }
 
+      if (pni) {
+        const existing = byPni[pni];
+        if (!existing) {
+          byPni[pni] = conversation;
+        } else {
+          log.warn(`checkForConflicts: Found conflict with pni ${pni}`);
+
+          // Keep the newer one if it has a uuid, otherwise keep existing
+          if (conversation.get('uuid')) {
+            // Keep new one
+            // eslint-disable-next-line no-await-in-loop
+            await this.combineConversations(conversation, existing);
+            byPni[pni] = conversation;
+          } else {
+            // Keep existing - note that this applies if neither had an e164
+            // eslint-disable-next-line no-await-in-loop
+            await this.combineConversations(existing, conversation);
+          }
+        }
+      }
+
       if (e164) {
         const existing = byE164[e164];
         if (!existing) {
@@ -619,100 +821,110 @@ export class ConversationController {
     current: ConversationModel,
     obsolete: ConversationModel
   ): Promise<void> {
-    const conversationType = current.get('type');
+    return this._combineConversationsQueue.add(async () => {
+      const conversationType = current.get('type');
 
-    if (obsolete.get('type') !== conversationType) {
-      assert(
-        false,
-        'combineConversations cannot combine a private and group conversation. Doing nothing'
-      );
-      return;
-    }
-
-    const obsoleteId = obsolete.get('id');
-    const obsoleteUuid = obsolete.getUuid();
-    const currentId = current.get('id');
-    log.warn('combineConversations: Combining two conversations', {
-      obsolete: obsoleteId,
-      current: currentId,
-    });
-
-    if (conversationType === 'private' && obsoleteUuid) {
-      if (!current.get('profileKey') && obsolete.get('profileKey')) {
+      if (!this.get(obsolete.id)) {
         log.warn(
-          'combineConversations: Copying profile key from old to new contact'
+          `combineConversations: Already combined obsolete conversation ${obsolete.id}`
         );
-
-        const profileKey = obsolete.get('profileKey');
-
-        if (profileKey) {
-          await current.setProfileKey(profileKey);
-        }
       }
 
-      log.warn(
-        'combineConversations: Delete all sessions tied to old conversationId'
-      );
-      const ourUuid = window.textsecure.storage.user.getCheckedUuid();
-      const deviceIds = await window.textsecure.storage.protocol.getDeviceIds({
-        ourUuid,
-        identifier: obsoleteUuid.toString(),
+      if (obsolete.get('type') !== conversationType) {
+        assert(
+          false,
+          'combineConversations cannot combine a private and group conversation. Doing nothing'
+        );
+        return;
+      }
+
+      const obsoleteId = obsolete.get('id');
+      const obsoleteUuid = obsolete.getUuid();
+      const currentId = current.get('id');
+      log.warn('combineConversations: Combining two conversations', {
+        obsolete: obsoleteId,
+        current: currentId,
       });
-      await Promise.all(
-        deviceIds.map(async deviceId => {
-          const addr = new QualifiedAddress(
-            ourUuid,
-            new Address(obsoleteUuid, deviceId)
+
+      if (conversationType === 'private' && obsoleteUuid) {
+        if (!current.get('profileKey') && obsolete.get('profileKey')) {
+          log.warn(
+            'combineConversations: Copying profile key from old to new contact'
           );
-          await window.textsecure.storage.protocol.removeSession(addr);
-        })
-      );
 
-      log.warn(
-        'combineConversations: Delete all identity information tied to old conversationId'
-      );
+          const profileKey = obsolete.get('profileKey');
 
-      if (obsoleteUuid) {
-        await window.textsecure.storage.protocol.removeIdentityKey(
-          obsoleteUuid
+          if (profileKey) {
+            await current.setProfileKey(profileKey);
+          }
+        }
+
+        log.warn(
+          'combineConversations: Delete all sessions tied to old conversationId'
         );
+        const ourUuid = window.textsecure.storage.user.getCheckedUuid();
+        const deviceIds = await window.textsecure.storage.protocol.getDeviceIds(
+          {
+            ourUuid,
+            identifier: obsoleteUuid.toString(),
+          }
+        );
+        await Promise.all(
+          deviceIds.map(async deviceId => {
+            const addr = new QualifiedAddress(
+              ourUuid,
+              new Address(obsoleteUuid, deviceId)
+            );
+            await window.textsecure.storage.protocol.removeSession(addr);
+          })
+        );
+
+        log.warn(
+          'combineConversations: Delete all identity information tied to old conversationId'
+        );
+
+        if (obsoleteUuid) {
+          await window.textsecure.storage.protocol.removeIdentityKey(
+            obsoleteUuid
+          );
+        }
+
+        log.warn(
+          'combineConversations: Ensure that all V1 groups have new conversationId instead of old'
+        );
+        const groups = await this.getAllGroupsInvolvingUuid(obsoleteUuid);
+        groups.forEach(group => {
+          const members = group.get('members');
+          const withoutObsolete = without(members, obsoleteId);
+          const currentAdded = uniq([...withoutObsolete, currentId]);
+
+          group.set({
+            members: currentAdded,
+          });
+          updateConversation(group.attributes);
+        });
       }
 
+      // Note: we explicitly don't want to update V2 groups
+
       log.warn(
-        'combineConversations: Ensure that all V1 groups have new conversationId instead of old'
+        'combineConversations: Delete the obsolete conversation from the database'
       );
-      const groups = await this.getAllGroupsInvolvingUuid(obsoleteUuid);
-      groups.forEach(group => {
-        const members = group.get('members');
-        const withoutObsolete = without(members, obsoleteId);
-        const currentAdded = uniq([...withoutObsolete, currentId]);
+      await removeConversation(obsoleteId);
 
-        group.set({
-          members: currentAdded,
-        });
-        updateConversation(group.attributes);
+      log.warn('combineConversations: Update messages table');
+      await migrateConversationMessages(obsoleteId, currentId);
+
+      log.warn(
+        'combineConversations: Eliminate old conversation from ConversationController lookups'
+      );
+      this._conversations.remove(obsolete);
+      this._conversations.resetLookups();
+
+      log.warn('combineConversations: Complete!', {
+        obsolete: obsoleteId,
+        current: currentId,
       });
-    }
-
-    // Note: we explicitly don't want to update V2 groups
-
-    log.warn(
-      'combineConversations: Delete the obsolete conversation from the database'
-    );
-    await removeConversation(obsoleteId);
-
-    log.warn('combineConversations: Update messages table');
-    await migrateConversationMessages(obsoleteId, currentId);
-
-    log.warn(
-      'combineConversations: Eliminate old conversation from ConversationController lookups'
-    );
-    this._conversations.remove(obsolete);
-    this._conversations.resetLookups();
-
-    log.warn('combineConversations: Complete!', {
-      obsolete: obsoleteId,
-      current: currentId,
     });
   }
 
diff --git a/ts/SignalProtocolStore.ts b/ts/SignalProtocolStore.ts
index db6bfb8d0..8a4db04b7 100644
--- a/ts/SignalProtocolStore.ts
+++ b/ts/SignalProtocolStore.ts
@@ -1045,11 +1045,11 @@ export class SignalProtocolStore extends EventsMixin {
       }
       const { uuid, deviceId } = qualifiedAddress;
 
-      const conversationId = window.ConversationController.ensureContactIds({
+      const conversation = window.ConversationController.lookupOrCreate({
         uuid: uuid.toString(),
       });
       strictAssert(
-        conversationId !== undefined,
+        conversation !== undefined,
         'storeSession: Ensure contact ids failed'
       );
       const id = qualifiedAddress.toString();
@@ -1059,7 +1059,7 @@ export class SignalProtocolStore extends EventsMixin {
           id,
           version: 2,
           ourUuid: qualifiedAddress.ourUuid.toString(),
-          conversationId,
+          conversationId: conversation.id,
           uuid: uuid.toString(),
           deviceId,
           record: record.serialize().toString('base64'),
@@ -1376,12 +1376,9 @@ export class SignalProtocolStore extends EventsMixin {
       const { uuid } = qualifiedAddress;
 
       // First, fetch this conversation
-      const conversationId = window.ConversationController.ensureContactIds({
+      const conversation = window.ConversationController.lookupOrCreate({
         uuid: uuid.toString(),
       });
-      assert(conversationId, `lightSessionReset/${id}: missing conversationId`);
-
-      const conversation = window.ConversationController.get(conversationId);
       assert(conversation, `lightSessionReset/${id}: missing conversation`);
 
       log.warn(`lightSessionReset/${id}: Resetting session`);
diff --git a/ts/background.ts b/ts/background.ts
index 1171ac181..204d97567 100644
--- a/ts/background.ts
+++ b/ts/background.ts
@@ -2593,12 +2593,13 @@ export async function startApp(): Promise<void> {
 
     let conversation;
 
-    const senderId = window.ConversationController.ensureContactIds({
-      e164: sender,
-      uuid: senderUuid,
-      highTrust: true,
-      reason: `onTyping(${typing.timestamp})`,
-    });
+    const senderConversation = window.ConversationController.maybeMergeContacts(
+      {
+        e164: sender,
+        aci: senderUuid,
+        reason: `onTyping(${typing.timestamp})`,
+      }
+    );
 
     // We multiplex between GV1/GV2 groups here, but we don't kick off migrations
     if (groupV2Id) {
@@ -2607,14 +2608,14 @@ export async function startApp(): Promise<void> {
     if (!conversation && groupId) {
       conversation = window.ConversationController.get(groupId);
     }
-    if (!groupV2Id && !groupId && senderId) {
-      conversation = window.ConversationController.get(senderId);
+    if (!groupV2Id && !groupId && senderConversation) {
+      conversation = senderConversation;
     }
 
     const ourId = window.ConversationController.getOurConversationId();
 
-    if (!senderId) {
-      log.warn('onTyping: ensureContactIds returned falsey senderId!');
+    if (!senderConversation) {
+      log.warn('onTyping: maybeMergeContacts returned falsey sender!');
       return;
     }
     if (!ourId) {
@@ -2648,7 +2649,6 @@ export async function startApp(): Promise<void> {
       );
       return;
     }
-    const senderConversation = window.ConversationController.get(senderId);
     if (!senderConversation) {
       log.warn('onTyping: No conversation for sender!');
       return;
@@ -2660,6 +2660,7 @@ export async function startApp(): Promise<void> {
       return;
     }
 
+    const senderId = senderConversation.id;
     conversation.notifyTyping({
       isTyping: started,
       fromMe: senderId === ourId,
@@ -2728,14 +2729,12 @@ export async function startApp(): Promise<void> {
       return;
     }
 
-    const detailsId = window.ConversationController.ensureContactIds({
+    const conversation = window.ConversationController.maybeMergeContacts({
       e164: details.number,
-      uuid: details.uuid,
-      highTrust: true,
+      aci: details.uuid,
       reason: 'onContactReceived',
     });
-    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-    const conversation = window.ConversationController.get(detailsId)!;
+    strictAssert(conversation, 'need conversation to queue the job!');
 
     // It's important to use queueJob here because we might update the expiration timer
     //   and we don't want conflicts with incoming message processing happening on the
@@ -2918,10 +2917,9 @@ export async function startApp(): Promise<void> {
   function onEnvelopeReceived({ envelope }: EnvelopeEvent) {
     const ourUuid = window.textsecure.storage.user.getUuid()?.toString();
     if (envelope.sourceUuid && envelope.sourceUuid !== ourUuid) {
-      window.ConversationController.ensureContactIds({
+      window.ConversationController.maybeMergeContacts({
         e164: envelope.source,
-        uuid: envelope.sourceUuid,
-        highTrust: true,
+        aci: envelope.sourceUuid,
         reason: `onEnvelopeReceived(${envelope.timestamp})`,
       });
     }
@@ -2991,11 +2989,11 @@ export async function startApp(): Promise<void> {
         reaction.targetTimestamp,
         'Reaction without targetTimestamp'
       );
-      const fromId = window.ConversationController.ensureContactIds({
+      const fromConversation = window.ConversationController.lookupOrCreate({
         e164: data.source,
         uuid: data.sourceUuid,
       });
-      strictAssert(fromId, 'Reaction without fromId');
+      strictAssert(fromConversation, 'Reaction without fromConversation');
 
       log.info('Queuing incoming reaction for', reaction.targetTimestamp);
       const attributes: ReactionAttributesType = {
@@ -3004,7 +3002,7 @@ export async function startApp(): Promise<void> {
         targetAuthorUuid,
         targetTimestamp: reaction.targetTimestamp,
         timestamp,
-        fromId,
+        fromId: fromConversation.id,
         source: ReactionSource.FromSomeoneElse,
       };
       const reactionModel = Reactions.getSingleton().add(attributes);
@@ -3024,16 +3022,16 @@ export async function startApp(): Promise<void> {
         'Delete missing targetSentTimestamp'
       );
       strictAssert(data.serverTimestamp, 'Delete missing serverTimestamp');
-      const fromId = window.ConversationController.ensureContactIds({
+      const fromConversation = window.ConversationController.lookupOrCreate({
         e164: data.source,
         uuid: data.sourceUuid,
       });
-      strictAssert(fromId, 'Delete missing fromId');
+      strictAssert(fromConversation, 'Delete missing fromConversation');
 
       const attributes: DeleteAttributesType = {
         targetSentTimestamp: del.targetSentTimestamp,
         serverTimestamp: data.serverTimestamp,
-        fromId,
+        fromId: fromConversation.id,
       };
       const deleteModel = Deletes.getSingleton().add(attributes);
 
@@ -3056,13 +3054,11 @@ export async function startApp(): Promise<void> {
   }
 
   async function onProfileKeyUpdate({ data, confirm }: ProfileKeyUpdateEvent) {
-    const conversationId = window.ConversationController.ensureContactIds({
+    const conversation = window.ConversationController.maybeMergeContacts({
+      aci: data.sourceUuid,
       e164: data.source,
-      uuid: data.sourceUuid,
-      highTrust: true,
       reason: 'onProfileKeyUpdate',
     });
-    const conversation = window.ConversationController.get(conversationId);
 
     if (!conversation) {
       log.error(
@@ -3141,19 +3137,17 @@ export async function startApp(): Promise<void> {
           result: SendStateByConversationId,
           { destinationUuid, destination, isAllowedToReplyToStory }
         ) => {
-          const conversationId = window.ConversationController.ensureContactIds(
-            {
-              uuid: destinationUuid,
-              e164: destination,
-            }
-          );
-          if (!conversationId || conversationId === ourId) {
+          const conversation = window.ConversationController.lookupOrCreate({
+            uuid: destinationUuid,
+            e164: destination,
+          });
+          if (!conversation || conversation.id === ourId) {
             return result;
           }
 
           return {
             ...result,
-            [conversationId]: {
+            [conversation.id]: {
               isAllowedToReplyToStory,
               status: SendStatus.Sent,
               updatedAt: timestamp,
@@ -3283,15 +3277,14 @@ export async function startApp(): Promise<void> {
       }
 
       // If we can't find one, we treat this as a normal GroupV1 group
-      const fromContactId = window.ConversationController.ensureContactIds({
+      const fromContact = window.ConversationController.maybeMergeContacts({
+        aci: sourceUuid,
         e164: source,
-        uuid: sourceUuid,
-        highTrust: true,
         reason: `getMessageDescriptor(${message.timestamp}): group v1`,
       });
 
       const conversationId = window.ConversationController.ensureGroup(id, {
-        addedBy: fromContactId,
+        addedBy: fromContact?.id,
       });
 
       return {
@@ -3300,22 +3293,21 @@ export async function startApp(): Promise<void> {
       };
     }
 
-    const id = window.ConversationController.ensureContactIds({
+    const conversation = window.ConversationController.maybeMergeContacts({
+      aci: destinationUuid,
       e164: destination,
-      uuid: destinationUuid,
-      highTrust: true,
       reason: `getMessageDescriptor(${message.timestamp}): private`,
     });
-    if (!id) {
+    if (!conversation) {
       confirm();
       throw new Error(
-        `getMessageDescriptor/${message.timestamp}: ensureContactIds returned falsey id`
+        `getMessageDescriptor/${message.timestamp}: maybeMergeContacts returned falsey conversation`
       );
     }
 
     return {
       type: Message.PRIVATE,
-      id,
+      id: conversation.id,
     };
   };
 
@@ -3726,11 +3718,10 @@ export async function startApp(): Promise<void> {
   }>): void {
     const { envelopeTimestamp, timestamp, source, sourceUuid, sourceDevice } =
       event.receipt;
-    const sourceConversationId = window.ConversationController.ensureContactIds(
+    const sourceConversation = window.ConversationController.maybeMergeContacts(
       {
+        aci: sourceUuid,
         e164: source,
-        uuid: sourceUuid,
-        highTrust: true,
         reason: `onReadOrViewReceipt(${envelopeTimestamp})`,
       }
     );
@@ -3740,14 +3731,14 @@ export async function startApp(): Promise<void> {
       sourceUuid,
       sourceDevice,
       envelopeTimestamp,
-      sourceConversationId,
+      sourceConversation?.id,
       'for sent message',
       timestamp
     );
 
     event.confirm();
 
-    if (!window.storage.get('read-receipt-setting') || !sourceConversationId) {
+    if (!window.storage.get('read-receipt-setting') || !sourceConversation) {
       return;
     }
 
@@ -3760,7 +3751,7 @@ export async function startApp(): Promise<void> {
     const attributes: MessageReceiptAttributesType = {
       messageSentAt: timestamp,
       receiptTimestamp: envelopeTimestamp,
-      sourceConversationId,
+      sourceConversationId: sourceConversation?.id,
       sourceUuid,
       sourceDevice,
       type,
@@ -3774,10 +3765,11 @@ export async function startApp(): Promise<void> {
   function onReadSync(ev: ReadSyncEvent) {
     const { envelopeTimestamp, sender, senderUuid, timestamp } = ev.read;
     const readAt = envelopeTimestamp;
-    const senderId = window.ConversationController.ensureContactIds({
+    const senderConversation = window.ConversationController.lookupOrCreate({
       e164: sender,
       uuid: senderUuid,
     });
+    const senderId = senderConversation?.id;
 
     log.info(
       'read sync',
@@ -3811,10 +3803,11 @@ export async function startApp(): Promise<void> {
 
   function onViewSync(ev: ViewSyncEvent) {
     const { envelopeTimestamp, senderE164, senderUuid, timestamp } = ev.view;
-    const senderId = window.ConversationController.ensureContactIds({
+    const senderConversation = window.ConversationController.lookupOrCreate({
       e164: senderE164,
       uuid: senderUuid,
     });
+    const senderId = senderConversation?.id;
 
     log.info(
       'view sync',
@@ -3853,11 +3846,10 @@ export async function startApp(): Promise<void> {
 
     ev.confirm();
 
-    const sourceConversationId = window.ConversationController.ensureContactIds(
+    const sourceConversation = window.ConversationController.maybeMergeContacts(
       {
+        aci: sourceUuid,
         e164: source,
-        uuid: sourceUuid,
-        highTrust: true,
         reason: `onDeliveryReceipt(${envelopeTimestamp})`,
       }
     );
@@ -3867,13 +3859,13 @@ export async function startApp(): Promise<void> {
       source,
       sourceUuid,
       sourceDevice,
-      sourceConversationId,
+      sourceConversation?.id,
       envelopeTimestamp,
       'for sent message',
       timestamp
     );
 
-    if (!sourceConversationId) {
+    if (!sourceConversation) {
       log.info('no conversation for', source, sourceUuid);
       return;
     }
@@ -3891,7 +3883,7 @@ export async function startApp(): Promise<void> {
     const attributes: MessageReceiptAttributesType = {
       messageSentAt: timestamp,
       receiptTimestamp: envelopeTimestamp,
-      sourceConversationId,
+      sourceConversationId: sourceConversation?.id,
       sourceUuid,
       sourceDevice,
       type: MessageReceiptType.Delivery,
diff --git a/ts/groups.ts b/ts/groups.ts
index fe00cd633..f1fa820ba 100644
--- a/ts/groups.ts
+++ b/ts/groups.ts
@@ -2501,11 +2501,11 @@ export function buildMigrationBubble(
     ...(newAttributes.membersV2 || []).map(item => item.uuid),
     ...(newAttributes.pendingMembersV2 || []).map(item => item.uuid),
   ].map(uuid => {
-    const conversationId = window.ConversationController.ensureContactIds({
+    const conversation = window.ConversationController.lookupOrCreate({
       uuid,
     });
-    strictAssert(conversationId, `Conversation not found for ${uuid}`);
-    return conversationId;
+    strictAssert(conversation, `Conversation not found for ${uuid}`);
+    return conversation.id;
   });
   const droppedMemberIds: Array<string> = difference(
     previousGroupV1MembersIds,
diff --git a/ts/messageModifiers/MessageRequests.ts b/ts/messageModifiers/MessageRequests.ts
index 581c1c978..7a9f5ca1f 100644
--- a/ts/messageModifiers/MessageRequests.ts
+++ b/ts/messageModifiers/MessageRequests.ts
@@ -103,12 +103,10 @@ export class MessageRequests extends Collection<MessageRequestModel> {
         conversation = window.ConversationController.get(groupId);
       }
       if (!conversation && (threadE164 || threadUuid)) {
-        conversation = window.ConversationController.get(
-          window.ConversationController.ensureContactIds({
-            e164: threadE164,
-            uuid: threadUuid,
-          })
-        );
+        conversation = window.ConversationController.lookupOrCreate({
+          e164: threadE164,
+          uuid: threadUuid,
+        });
       }
 
       if (!conversation) {
diff --git a/ts/messageModifiers/Reactions.ts b/ts/messageModifiers/Reactions.ts
index 99f96eb98..a6a5e569c 100644
--- a/ts/messageModifiers/Reactions.ts
+++ b/ts/messageModifiers/Reactions.ts
@@ -44,11 +44,11 @@ export class Reactions extends Collection<ReactionModel> {
     const senderId = getContactId(message.attributes);
     const sentAt = message.get('sent_at');
     const reactionsBySource = this.filter(re => {
-      const targetSenderId = window.ConversationController.ensureContactIds({
+      const targetSender = window.ConversationController.lookupOrCreate({
         uuid: re.get('targetAuthorUuid'),
       });
       const targetTimestamp = re.get('targetTimestamp');
-      return targetSenderId === senderId && targetTimestamp === sentAt;
+      return targetSender?.id === senderId && targetTimestamp === sentAt;
     });
 
     if (reactionsBySource.length > 0) {
@@ -87,13 +87,14 @@ export class Reactions extends Collection<ReactionModel> {
     try {
       // The conversation the target message was in; we have to find it in the database
       //   to to figure that out.
-      const targetConversationId =
-        window.ConversationController.ensureContactIds({
+      const targetAuthorConversation =
+        window.ConversationController.lookupOrCreate({
           uuid: reaction.get('targetAuthorUuid'),
         });
+      const targetConversationId = targetAuthorConversation?.id;
       if (!targetConversationId) {
         throw new Error(
-          'onReaction: No conversationId returned from ensureContactIds!'
+          'onReaction: No conversationId returned from lookupOrCreate!'
         );
       }
 
diff --git a/ts/messageModifiers/ReadSyncs.ts b/ts/messageModifiers/ReadSyncs.ts
index 6b4b4f745..b98229b7a 100644
--- a/ts/messageModifiers/ReadSyncs.ts
+++ b/ts/messageModifiers/ReadSyncs.ts
@@ -58,13 +58,13 @@ export class ReadSyncs extends Collection {
   }
 
   forMessage(message: MessageModel): ReadSyncModel | null {
-    const senderId = window.ConversationController.ensureContactIds({
+    const sender = window.ConversationController.lookupOrCreate({
       e164: message.get('source'),
       uuid: message.get('sourceUuid'),
     });
     const sync = this.find(item => {
       return (
-        item.get('senderId') === senderId &&
+        item.get('senderId') === sender?.id &&
         item.get('timestamp') === message.get('sent_at')
       );
     });
@@ -84,12 +84,12 @@ export class ReadSyncs extends Collection {
       );
 
       const found = messages.find(item => {
-        const senderId = window.ConversationController.ensureContactIds({
+        const sender = window.ConversationController.lookupOrCreate({
           e164: item.source,
           uuid: item.sourceUuid,
         });
 
-        return isIncoming(item) && senderId === sync.get('senderId');
+        return isIncoming(item) && sender?.id === sync.get('senderId');
       });
 
       if (!found) {
diff --git a/ts/messageModifiers/ViewSyncs.ts b/ts/messageModifiers/ViewSyncs.ts
index d338256d3..2f1df154f 100644
--- a/ts/messageModifiers/ViewSyncs.ts
+++ b/ts/messageModifiers/ViewSyncs.ts
@@ -35,13 +35,13 @@ export class ViewSyncs extends Collection {
   }
 
   forMessage(message: MessageModel): Array<ViewSyncModel> {
-    const senderId = window.ConversationController.ensureContactIds({
+    const sender = window.ConversationController.lookupOrCreate({
       e164: message.get('source'),
       uuid: message.get('sourceUuid'),
     });
     const syncs = this.filter(item => {
       return (
-        item.get('senderId') === senderId &&
+        item.get('senderId') === sender?.id &&
         item.get('timestamp') === message.get('sent_at')
       );
     });
@@ -63,12 +63,12 @@ export class ViewSyncs extends Collection {
       );
 
       const found = messages.find(item => {
-        const senderId = window.ConversationController.ensureContactIds({
+        const sender = window.ConversationController.lookupOrCreate({
           e164: item.source,
           uuid: item.sourceUuid,
         });
 
-        return senderId === sync.get('senderId');
+        return sender?.id === sync.get('senderId');
       });
 
       if (!found) {
diff --git a/ts/messages/helpers.ts b/ts/messages/helpers.ts
index 44925d040..46998e20d 100644
--- a/ts/messages/helpers.ts
+++ b/ts/messages/helpers.ts
@@ -36,7 +36,7 @@ export function isQuoteAMatch(
   }
 
   const { authorUuid, id } = quote;
-  const authorConversationId = window.ConversationController.ensureContactIds({
+  const authorConversation = window.ConversationController.lookupOrCreate({
     e164: 'author' in quote ? quote.author : undefined,
     uuid: authorUuid,
   });
@@ -44,7 +44,7 @@ export function isQuoteAMatch(
   return (
     message.sent_at === id &&
     message.conversationId === conversationId &&
-    getContactId(message) === authorConversationId
+    getContactId(message) === authorConversation?.id
   );
 }
 
@@ -58,10 +58,11 @@ export function getContactId(
     return window.ConversationController.getOurConversationId();
   }
 
-  return window.ConversationController.ensureContactIds({
+  const conversation = window.ConversationController.lookupOrCreate({
     e164: source,
     uuid: sourceUuid,
   });
+  return conversation?.id;
 }
 
 export function getContact(
diff --git a/ts/model-types.d.ts b/ts/model-types.d.ts
index 14f1138d7..9b948dfad 100644
--- a/ts/model-types.d.ts
+++ b/ts/model-types.d.ts
@@ -322,6 +322,7 @@ export type ConversationAttributesType = {
 
   // Private core info
   uuid?: UUIDStringType;
+  pni?: UUIDStringType;
   e164?: string;
 
   // Private other fields
diff --git a/ts/models/conversations.ts b/ts/models/conversations.ts
index e411a9ed9..40d3f1e91 100644
--- a/ts/models/conversations.ts
+++ b/ts/models/conversations.ts
@@ -1275,11 +1275,11 @@ export class ConversationModel extends window.Backbone
     const e164 = message.get('source');
     const sourceDevice = message.get('sourceDevice');
 
-    const sourceId = window.ConversationController.ensureContactIds({
+    const source = window.ConversationController.lookupOrCreate({
       uuid,
       e164,
     });
-    const typingToken = `${sourceId}.${sourceDevice}`;
+    const typingToken = `${source?.id}.${sourceDevice}`;
 
     // Clear typing indicator for a given contact if we receive a message from them
     this.clearContactTypingTimer(typingToken);
@@ -1869,10 +1869,10 @@ export class ConversationModel extends window.Backbone
 
   updateE164(e164?: string | null): void {
     const oldValue = this.get('e164');
-    if (e164 && e164 !== oldValue) {
-      this.set('e164', e164);
+    if (e164 !== oldValue) {
+      this.set('e164', e164 || undefined);
 
-      if (oldValue) {
+      if (oldValue && e164) {
         this.addChangeNumberNotification(oldValue, e164);
       }
 
@@ -1883,13 +1883,32 @@ export class ConversationModel extends window.Backbone
 
   updateUuid(uuid?: string): void {
     const oldValue = this.get('uuid');
-    if (uuid && uuid !== oldValue) {
-      this.set('uuid', UUID.cast(uuid.toLowerCase()));
+    if (uuid !== oldValue) {
+      this.set('uuid', uuid ? UUID.cast(uuid.toLowerCase()) : undefined);
       window.Signal.Data.updateConversation(this.attributes);
       this.trigger('idUpdated', this, 'uuid', oldValue);
     }
   }
 
+  updatePni(pni?: string): void {
+    const oldValue = this.get('pni');
+    if (pni !== oldValue) {
+      this.set('pni', pni ? UUID.cast(pni.toLowerCase()) : undefined);
+
+      if (
+        oldValue &&
+        pni &&
+        (!this.get('uuid') || this.get('uuid') === oldValue)
+      ) {
+        // TODO: DESKTOP-3974
+        this.addKeyChange(UUID.checkedLookup(oldValue));
+      }
+
+      window.Signal.Data.updateConversation(this.attributes);
+      this.trigger('idUpdated', this, 'pni', oldValue);
+    }
+  }
+
   updateGroupId(groupId?: string): void {
     const oldValue = this.get('groupId');
     if (groupId && groupId !== oldValue) {
@@ -5389,6 +5408,9 @@ window.Whisper.ConversationCollection = window.Backbone.Collection.extend({
           if (idProp === 'uuid') {
             delete this._byUuid[oldValue];
           }
+          if (idProp === 'pni') {
+            delete this._byPni[oldValue];
+          }
           if (idProp === 'groupId') {
             delete this._byGroupId[oldValue];
           }
@@ -5401,6 +5423,10 @@ window.Whisper.ConversationCollection = window.Backbone.Collection.extend({
         if (uuid) {
           this._byUuid[uuid] = model;
         }
+        const pni = model.get('pni');
+        if (pni) {
+          this._byPni[pni] = model;
+        }
         const groupId = model.get('groupId');
         if (groupId) {
           this._byGroupId[groupId] = model;
@@ -5441,6 +5467,16 @@ window.Whisper.ConversationCollection = window.Backbone.Collection.extend({
         }
       }
 
+      const pni = model.get('pni');
+      if (pni) {
+        const existing = this._byPni[pni];
+
+        // Prefer the contact with both uuid and pni
+        if (!existing || (existing && !existing.get('uuid'))) {
+          this._byPni[pni] = model;
+        }
+      }
+
       const groupId = model.get('groupId');
       if (groupId) {
         this._byGroupId[groupId] = model;
@@ -5451,6 +5487,7 @@ window.Whisper.ConversationCollection = window.Backbone.Collection.extend({
   eraseLookups() {
     this._byE164 = Object.create(null);
     this._byUuid = Object.create(null);
+    this._byPni = Object.create(null);
     this._byGroupId = Object.create(null);
   },
 
@@ -5510,6 +5547,7 @@ window.Whisper.ConversationCollection = window.Backbone.Collection.extend({
       this._byE164[id] ||
       this._byE164[`+${id}`] ||
       this._byUuid[id] ||
+      this._byPni[id] ||
       this._byGroupId[id] ||
       window.Backbone.Collection.prototype.get.call(this, id)
     );
diff --git a/ts/models/messages.ts b/ts/models/messages.ts
index 874ba531d..337fab00c 100644
--- a/ts/models/messages.ts
+++ b/ts/models/messages.ts
@@ -291,12 +291,12 @@ export class MessageModel extends window.Backbone.Model<MessageAttributesType> {
     const sourceDevice = this.get('sourceDevice');
 
     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-    const sourceId = window.ConversationController.ensureContactIds({
+    const conversation = window.ConversationController.lookupOrCreate({
       e164: source,
       uuid: sourceUuid,
     })!;
 
-    return `${sourceId}.${sourceDevice}-${sentAt}`;
+    return `${conversation?.id}.${sourceDevice}-${sentAt}`;
   }
 
   getReceivedAt(): number {
@@ -2137,14 +2137,13 @@ export class MessageModel extends window.Backbone.Model<MessageAttributesType> {
                 return;
               }
 
-              const destinationConversationId =
-                window.ConversationController.ensureContactIds({
-                  uuid: destinationUuid,
-                  e164: destination,
-                  highTrust: true,
+              const destinationConversation =
+                window.ConversationController.maybeMergeContacts({
+                  aci: destinationUuid,
+                  e164: destination || undefined,
                   reason: `handleDataMessage(${initialMessage.timestamp})`,
                 });
-              if (!destinationConversationId) {
+              if (!destinationConversation) {
                 return;
               }
 
@@ -2155,9 +2154,9 @@ export class MessageModel extends window.Backbone.Model<MessageAttributesType> {
 
               const previousSendState = getOwn(
                 sendStateByConversationId,
-                destinationConversationId
+                destinationConversation.id
               );
-              sendStateByConversationId[destinationConversationId] =
+              sendStateByConversationId[destinationConversation.id] =
                 previousSendState
                   ? sendStateReducer(previousSendState, {
                       type: SendActionType.Sent,
@@ -2274,7 +2273,7 @@ export class MessageModel extends window.Backbone.Model<MessageAttributesType> {
         UUIDKind.ACI
       );
       // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-      const senderId = window.ConversationController.ensureContactIds({
+      const sender = window.ConversationController.lookupOrCreate({
         e164: source,
         uuid: sourceUuid,
       })!;
@@ -2348,7 +2347,7 @@ export class MessageModel extends window.Backbone.Model<MessageAttributesType> {
       // Drop incoming messages to announcement only groups where sender is not admin
       if (
         conversation.get('announcementsOnly') &&
-        !conversation.isAdmin(UUID.checkedLookup(senderId))
+        !conversation.isAdmin(UUID.checkedLookup(sender?.id))
       ) {
         confirm();
         return;
@@ -2565,8 +2564,6 @@ export class MessageModel extends window.Backbone.Model<MessageAttributesType> {
                 conversation.set({ addedBy: getContactId(message.attributes) });
               }
             } else if (initialMessage.group.type === GROUP_TYPES.QUIT) {
-              // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-              const sender = window.ConversationController.get(senderId)!;
               const inGroup = Boolean(
                 sender &&
                   (conversation.get('members') || []).includes(sender.id)
@@ -2682,14 +2679,11 @@ export class MessageModel extends window.Backbone.Model<MessageAttributesType> {
             } else if (isDirectConversation(conversation.attributes)) {
               conversation.setProfileKey(profileKey);
             } else {
-              const localId = window.ConversationController.ensureContactIds({
+              const local = window.ConversationController.lookupOrCreate({
                 e164: source,
                 uuid: sourceUuid,
               });
-              // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-              window.ConversationController.get(localId)!.setProfileKey(
-                profileKey
-              );
+              local?.setProfileKey(profileKey);
             }
           }
 
diff --git a/ts/services/storageRecordOps.ts b/ts/services/storageRecordOps.ts
index d4de21f70..b726a4280 100644
--- a/ts/services/storageRecordOps.ts
+++ b/ts/services/storageRecordOps.ts
@@ -863,22 +863,16 @@ export async function mergeContactRecord(
     return { hasConflict: false, shouldDrop: true, details: ['our own uuid'] };
   }
 
-  const id = window.ConversationController.ensureContactIds({
+  const conversation = window.ConversationController.maybeMergeContacts({
+    aci: uuid,
     e164,
-    uuid,
-    highTrust: true,
     reason: 'mergeContactRecord',
   });
 
-  if (!id) {
-    throw new Error(`No ID for ${storageID}`);
+  if (!conversation) {
+    throw new Error(`No conversation for ${storageID}`);
   }
 
-  const conversation = await window.ConversationController.getOrCreateAndWait(
-    id,
-    'private'
-  );
-
   let needsProfileFetch = false;
   if (contactRecord.profileKey && contactRecord.profileKey.length > 0) {
     needsProfileFetch = await conversation.setProfileKey(
@@ -1129,32 +1123,32 @@ export async function mergeAccountRecord(
 
     const remotelyPinnedConversationPromises = pinnedConversations.map(
       async ({ contact, legacyGroupId, groupMasterKey }) => {
-        let conversationId: string | undefined;
+        let conversation: ConversationModel | undefined;
 
         if (contact) {
-          conversationId =
-            window.ConversationController.ensureContactIds(contact);
+          conversation = window.ConversationController.lookupOrCreate(contact);
         } else if (legacyGroupId && legacyGroupId.length) {
-          conversationId = Bytes.toBinary(legacyGroupId);
+          const groupId = Bytes.toBinary(legacyGroupId);
+          conversation = window.ConversationController.get(groupId);
         } else if (groupMasterKey && groupMasterKey.length) {
           const groupFields = deriveGroupFields(groupMasterKey);
           const groupId = Bytes.toBase64(groupFields.id);
 
-          conversationId = groupId;
+          conversation = window.ConversationController.get(groupId);
         } else {
           log.error(
             'storageService.mergeAccountRecord: Invalid identifier received'
           );
         }
 
-        if (!conversationId) {
+        if (!conversation) {
           log.error(
             'storageService.mergeAccountRecord: missing conversation id.'
           );
           return undefined;
         }
 
-        return window.ConversationController.get(conversationId);
+        return conversation;
       }
     );
 
diff --git a/ts/sql/Client.ts b/ts/sql/Client.ts
index 4a0563af4..eea321517 100644
--- a/ts/sql/Client.ts
+++ b/ts/sql/Client.ts
@@ -215,6 +215,7 @@ const dataInterface: ClientInterface = {
   updateConversation,
   updateConversations,
   removeConversation,
+  _removeAllConversations,
   updateAllConversationColors,
   removeAllProfileKeyCredentials,
 
@@ -1084,6 +1085,10 @@ async function removeConversation(id: string): Promise<void> {
   }
 }
 
+async function _removeAllConversations(): Promise<void> {
+  await channels._removeAllConversations();
+}
+
 async function eraseStorageServiceStateFromConversations(): Promise<void> {
   await channels.eraseStorageServiceStateFromConversations();
 }
diff --git a/ts/sql/Interface.ts b/ts/sql/Interface.ts
index 3fe6b09ee..3eff8c1b4 100644
--- a/ts/sql/Interface.ts
+++ b/ts/sql/Interface.ts
@@ -414,6 +414,7 @@ export type DataInterface = {
   // updateConversation is a normal data method on Server, a sync batch-add on Client
   updateConversations: (array: Array<ConversationType>) => Promise<void>;
   // removeConversation handles either one id or an array on Server, and one id on Client
+  _removeAllConversations: () => Promise<void>;
   updateAllConversationColors: (
     conversationColor?: ConversationColorType,
     customColorData?: {
diff --git a/ts/sql/Server.ts b/ts/sql/Server.ts
index 176ef953e..745f34d31 100644
--- a/ts/sql/Server.ts
+++ b/ts/sql/Server.ts
@@ -207,6 +207,7 @@ const dataInterface: ServerInterface = {
   updateConversation,
   updateConversations,
   removeConversation,
+  _removeAllConversations,
   updateAllConversationColors,
   removeAllProfileKeyCredentials,
 
@@ -1478,6 +1479,11 @@ async function removeConversation(id: Array<string> | string): Promise<void> {
   batchMultiVarQuery(db, id, removeConversationsSync);
 }
 
+async function _removeAllConversations(): Promise<void> {
+  const db = getInstance();
+  db.prepare<EmptyQuery>('DELETE from conversations;').run();
+}
+
 async function getConversationById(
   id: string
 ): Promise<ConversationType | undefined> {
diff --git a/ts/state/smart/CallManager.tsx b/ts/state/smart/CallManager.tsx
index 2c812e76d..5f0a6688b 100644
--- a/ts/state/smart/CallManager.tsx
+++ b/ts/state/smart/CallManager.tsx
@@ -121,10 +121,10 @@ const mapStateToActiveCallProp = (
   const conversationSelectorByUuid = memoize<
     (uuid: UUIDStringType) => undefined | ConversationType
   >(uuid => {
-    const conversationId = window.ConversationController.ensureContactIds({
+    const convoForUuid = window.ConversationController.lookupOrCreate({
       uuid,
     });
-    return conversationId ? conversationSelector(conversationId) : undefined;
+    return convoForUuid ? conversationSelector(convoForUuid.id) : undefined;
   });
 
   const baseResult = {
diff --git a/ts/test-electron/ConversationController_test.ts b/ts/test-electron/ConversationController_test.ts
new file mode 100644
index 000000000..49f22d45e
--- /dev/null
+++ b/ts/test-electron/ConversationController_test.ts
@@ -0,0 +1,865 @@
+// Copyright 2022 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { assert } from 'chai';
+
+import { UUID } from '../types/UUID';
+import { strictAssert } from '../util/assert';
+
+import type { ConversationModel } from '../models/conversations';
+import type { UUIDStringType } from '../types/UUID';
+
+const ACI_1 = UUID.generate().toString();
+const ACI_2 = UUID.generate().toString();
+const E164_1 = '+14155550111';
+const E164_2 = '+14155550112';
+const PNI_1 = UUID.generate().toString();
+const PNI_2 = UUID.generate().toString();
+const reason = 'test';
+
+type ParamsType = {
+  uuid?: UUIDStringType;
+  aci?: UUIDStringType;
+  e164?: string;
+  pni?: UUIDStringType;
+};
+
+describe('ConversationController', () => {
+  describe('maybeMergeContacts', () => {
+    let mergeOldAndNew: (options: {
+      logId: string;
+      oldConversation: ConversationModel;
+      newConversation: ConversationModel;
+    }) => Promise<void>;
+
+    beforeEach(async () => {
+      await window.Signal.Data._removeAllConversations();
+
+      window.ConversationController.reset();
+      await window.ConversationController.load();
+
+      mergeOldAndNew = () => {
+        throw new Error('mergeOldAndNew: Should not be called!');
+      };
+    });
+
+    // Verifying incoming data
+    describe('data validation', () => {
+      it('throws when provided no data', () => {
+        assert.throws(() => {
+          window.ConversationController.maybeMergeContacts({
+            mergeOldAndNew,
+            reason,
+          });
+        }, 'Need to provide at least one');
+      });
+      it('throws when provided a pni with no e164', () => {
+        assert.throws(() => {
+          window.ConversationController.maybeMergeContacts({
+            mergeOldAndNew,
+            pni: PNI_1,
+            reason,
+          });
+        }, 'Cannot provide pni without an e164');
+      });
+    });
+
+    function create(
+      name: string,
+      { uuid, aci, e164, pni }: ParamsType
+    ): ConversationModel {
+      const identifier = aci || uuid || e164 || pni;
+      const serviceId = aci || uuid || pni;
+
+      strictAssert(identifier, 'create needs aci, e164, pni, or uuid');
+
+      const conversation = window.ConversationController.getOrCreate(
+        identifier,
+        'private',
+        { uuid: serviceId, e164, pni }
+      );
+      expectLookups(conversation, name, { uuid, aci, e164, pni });
+
+      return conversation;
+    }
+
+    function expectLookups(
+      conversation: ConversationModel | undefined,
+      name: string,
+      { uuid, aci, e164, pni }: ParamsType
+    ) {
+      assert.exists(conversation, `${name} conversation exists`);
+
+      // Verify that this conversation hasn't been deleted
+      assert.strictEqual(
+        window.ConversationController.get(conversation?.id)?.id,
+        conversation?.id,
+        `${name} vs. lookup by id`
+      );
+
+      if (uuid) {
+        assert.strictEqual(
+          window.ConversationController.get(uuid)?.id,
+          conversation?.id,
+          `${name} vs. lookup by uuid`
+        );
+      }
+      if (aci) {
+        assert.strictEqual(
+          window.ConversationController.get(aci)?.id,
+          conversation?.id,
+          `${name} vs. lookup by aci`
+        );
+      }
+      if (e164) {
+        assert.strictEqual(
+          window.ConversationController.get(e164)?.id,
+          conversation?.id,
+          `${name} vs. lookup by e164`
+        );
+      }
+      if (pni) {
+        assert.strictEqual(
+          window.ConversationController.get(pni)?.id,
+          conversation?.id,
+          `${name} vs. lookup by pni`
+        );
+      }
+    }
+
+    function expectPropsAndLookups(
+      conversation: ConversationModel | undefined,
+      name: string,
+      { uuid, aci, e164, pni }: ParamsType
+    ) {
+      assert.exists(conversation, `${name} conversation exists`);
+      assert.strictEqual(
+        conversation?.get('uuid'),
+        aci || uuid,
+        `${name} uuid matches`
+      );
+      assert.strictEqual(
+        conversation?.get('e164'),
+        e164,
+        `${name} e164 matches`
+      );
+      assert.strictEqual(conversation?.get('pni'), pni, `${name} pni matches`);
+
+      expectLookups(conversation, name, { uuid, e164, pni });
+    }
+
+    function expectDeleted(conversation: ConversationModel, name: string) {
+      assert.isUndefined(
+        window.ConversationController.get(conversation.id),
+        `${name} has been deleted`
+      );
+    }
+
+    describe('non-destructive updates', () => {
+      it('creates a new conversation with just ACI if no matches', () => {
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          reason,
+        });
+
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_1,
+        });
+
+        const second = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          reason,
+        });
+
+        expectPropsAndLookups(second, 'second', {
+          aci: ACI_1,
+        });
+
+        assert.strictEqual(result?.id, second?.id, 'result and second match');
+      });
+      it('creates a new conversation with just e164 if no matches', () => {
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          e164: E164_1,
+          reason,
+        });
+
+        expectPropsAndLookups(result, 'result', {
+          e164: E164_1,
+        });
+
+        const second = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          e164: E164_1,
+          reason,
+        });
+
+        expectPropsAndLookups(second, 'second', {
+          e164: E164_1,
+        });
+
+        assert.strictEqual(result?.id, second?.id, 'result and second match');
+      });
+      it('creates a new conversation with all data if no matches', () => {
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        const second = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+
+        expectPropsAndLookups(second, 'second', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        assert.strictEqual(result?.id, second?.id, 'result and second match');
+      });
+
+      it('fetches all-data conversation with ACI-only query', () => {
+        const initial = create('initial', {
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          reason,
+        });
+
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        assert.strictEqual(result?.id, initial?.id, 'result and initial match');
+      });
+
+      it('fetches all-data conversation with e164+PNI query', () => {
+        const initial = create('initial', {
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        assert.strictEqual(result?.id, initial?.id, 'result and initial match');
+      });
+
+      it('adds ACI to conversation with e164+PNI', () => {
+        const initial = create('initial', {
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        assert.strictEqual(initial?.id, result?.id, 'result and initial match');
+      });
+      it('adds e164+PNI to conversation with just ACI', () => {
+        const initial = create('initial', {
+          uuid: ACI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        assert.strictEqual(result?.id, initial?.id, 'result and initial match');
+      });
+      it('adds e164 to conversation with ACI+PNI', () => {
+        const initial = create('initial', {
+          aci: ACI_1,
+          pni: PNI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        assert.strictEqual(result?.id, initial?.id, 'result and initial match');
+      });
+      it('adds PNI to conversation with ACI+e164', () => {
+        const initial = create('initial', {
+          aci: ACI_1,
+          e164: E164_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        assert.strictEqual(initial?.id, result?.id, 'result and initial match');
+      });
+      it('adds PNI to conversation with just e164', () => {
+        const initial = create('initial', {
+          e164: E164_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: PNI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        assert.strictEqual(initial?.id, result?.id, 'result and initial match');
+      });
+      it('adds PNI+ACI to conversation with just e164', () => {
+        const initial = create('initial', {
+          e164: E164_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        assert.strictEqual(initial?.id, result?.id, 'result and initial match');
+      });
+      it('adds ACI+e164 to conversation with just PNI', () => {
+        const initial = create('initial', {
+          pni: PNI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        assert.strictEqual(initial?.id, result?.id, 'result and initial match');
+      });
+
+      it('promotes PNI used as generic UUID to be in the PNI field as well', () => {
+        const initial = create('initial', {
+          aci: PNI_1,
+          e164: E164_1,
+        });
+        expectPropsAndLookups(initial, 'initial', {
+          uuid: PNI_1,
+          e164: E164_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: PNI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        assert.strictEqual(initial?.id, result?.id, 'result and initial match');
+      });
+    });
+
+    describe('with destructive updates', () => {
+      it('replaces e164+PNI in conversation with matching ACI', () => {
+        const initial = create('initial', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          e164: E164_2,
+          pni: PNI_2,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_1,
+          e164: E164_2,
+          pni: PNI_2,
+        });
+
+        assert.isUndefined(
+          window.ConversationController.get(E164_1),
+          'old e164 no longer found'
+        );
+        assert.isUndefined(
+          window.ConversationController.get(PNI_1),
+          'old pni no longer found'
+        );
+
+        assert.strictEqual(result?.id, initial?.id, 'result and initial match');
+      });
+
+      it('replaces PNI in conversation with e164+PNI', () => {
+        const initial = create('initial', {
+          pni: PNI_1,
+          e164: E164_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          pni: PNI_2,
+          e164: E164_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: PNI_2,
+          e164: E164_1,
+          pni: PNI_2,
+        });
+
+        assert.isUndefined(
+          window.ConversationController.get(PNI_1),
+          'old pni no longer found'
+        );
+
+        assert.strictEqual(result?.id, initial?.id, 'result and initial match');
+      });
+      it('replaces PNI in conversation with all data', () => {
+        const initial = create('initial', {
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_2,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_2,
+        });
+
+        assert.isUndefined(
+          window.ConversationController.get(PNI_1),
+          'old pni no longer found'
+        );
+
+        assert.strictEqual(result?.id, initial?.id, 'result and initial match');
+      });
+
+      it('removes e164+PNI from previous conversation with an ACI, adds all data to new conversation', () => {
+        const initial = create('initial', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_2,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_2,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        expectPropsAndLookups(initial, 'initial', { uuid: ACI_1 });
+
+        assert.notStrictEqual(
+          initial?.id,
+          result?.id,
+          'result and initial should not match'
+        );
+      });
+      it('removes e164+PNI from previous conversation with an ACI, adds to ACI match', () => {
+        const initial = create('initial', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+        const aciOnly = create('aciOnly', {
+          uuid: ACI_2,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_2,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(aciOnly, 'aciOnly', {
+          uuid: ACI_2,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        expectPropsAndLookups(initial, 'initial', { uuid: ACI_1 });
+
+        assert.strictEqual(
+          aciOnly?.id,
+          result?.id,
+          'result and aciOnly should match'
+        );
+      });
+
+      it('removes PNI from previous conversation, adds it to e164-only match', () => {
+        const withE164 = create('withE164', {
+          e164: E164_1,
+        });
+        const withPNI = create('withPNI', {
+          e164: E164_2,
+          pni: PNI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: PNI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        expectPropsAndLookups(withPNI, 'withPNI', { e164: E164_2 });
+
+        assert.strictEqual(
+          withE164?.id,
+          result?.id,
+          'result and initial should match'
+        );
+      });
+      it('removes PNI from previous conversation, adds it new e164+PNI conversation', () => {
+        const initial = create('initial', {
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          e164: E164_2,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: PNI_1,
+          e164: E164_2,
+          pni: PNI_1,
+        });
+
+        expectPropsAndLookups(initial, 'initial', { e164: E164_1 });
+
+        assert.notStrictEqual(
+          initial?.id,
+          result?.id,
+          'result and initial should not match'
+        );
+      });
+      it('deletes PNI-only previous conversation, adds it to e164 match', () => {
+        mergeOldAndNew = ({ oldConversation }) => {
+          window.ConversationController.dangerouslyRemoveById(
+            oldConversation.id
+          );
+          return Promise.resolve();
+        };
+
+        const withE164 = create('withE164', {
+          e164: E164_1,
+        });
+        const withPNI = create('withPNI', {
+          pni: PNI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: PNI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        expectDeleted(withPNI, 'withPNI');
+
+        assert.strictEqual(
+          withE164?.id,
+          result?.id,
+          'result and initial should match'
+        );
+      });
+      it('deletes previous conversation with PNI as UUID only, adds it to e164 match', () => {
+        mergeOldAndNew = ({ oldConversation }) => {
+          window.ConversationController.dangerouslyRemoveById(
+            oldConversation.id
+          );
+          return Promise.resolve();
+        };
+
+        const withE164 = create('withE164', {
+          e164: E164_1,
+        });
+        const withPNI = create('withPNI', {
+          uuid: PNI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: PNI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        expectDeleted(withPNI, 'withPNI');
+
+        assert.strictEqual(
+          withE164?.id,
+          result?.id,
+          'result and initial should match'
+        );
+      });
+      it('deletes e164+PNI previous conversation, adds data to ACI match', () => {
+        mergeOldAndNew = ({ oldConversation }) => {
+          window.ConversationController.dangerouslyRemoveById(
+            oldConversation.id
+          );
+          return Promise.resolve();
+        };
+
+        const withE164 = create('withE164', {
+          e164: E164_1,
+          pni: PNI_1,
+        });
+        const withACI = create('withPNI', {
+          aci: ACI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        expectDeleted(withE164, 'withE164');
+
+        assert.strictEqual(
+          withACI?.id,
+          result?.id,
+          'result and initial should match'
+        );
+      });
+
+      it('handles three matching conversations: ACI-only, with E164, and with PNI', () => {
+        const withACI = create('withACI', {
+          aci: ACI_1,
+        });
+        const withE164 = create('withE164', {
+          aci: ACI_2,
+          e164: E164_1,
+        });
+        const withPNI = create('withPNI', {
+          pni: PNI_1,
+          e164: E164_2,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+        expectPropsAndLookups(withE164, 'withE164', { aci: ACI_2 });
+        expectPropsAndLookups(withPNI, 'withPNI', { e164: E164_2 });
+
+        assert.strictEqual(result?.id, withACI?.id, 'result and withACI match');
+      });
+      it('handles three matching conversations: ACI-only, E164-only (deleted), and with PNI', () => {
+        mergeOldAndNew = ({ oldConversation }) => {
+          window.ConversationController.dangerouslyRemoveById(
+            oldConversation.id
+          );
+          return Promise.resolve();
+        };
+
+        const withACI = create('withACI', {
+          aci: ACI_1,
+        });
+        const withE164 = create('withE164', {
+          e164: E164_1,
+        });
+        const withPNI = create('withPNI', {
+          pni: PNI_1,
+          e164: E164_2,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+        expectPropsAndLookups(withPNI, 'withPNI', { e164: E164_2 });
+
+        expectDeleted(withE164, 'withE164');
+
+        assert.strictEqual(result?.id, withACI?.id, 'result and withACI match');
+      });
+      it('merges three matching conversations: ACI-only, E164-only (deleted), PNI-only (deleted)', () => {
+        mergeOldAndNew = ({ oldConversation }) => {
+          window.ConversationController.dangerouslyRemoveById(
+            oldConversation.id
+          );
+          return Promise.resolve();
+        };
+
+        const withACI = create('withACI', {
+          aci: ACI_1,
+        });
+        const withE164 = create('withE164', {
+          e164: E164_1,
+        });
+        const withPNI = create('withPNI', {
+          pni: PNI_1,
+        });
+
+        const result = window.ConversationController.maybeMergeContacts({
+          mergeOldAndNew,
+          aci: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+          reason,
+        });
+        expectPropsAndLookups(result, 'result', {
+          uuid: ACI_1,
+          e164: E164_1,
+          pni: PNI_1,
+        });
+
+        expectDeleted(withPNI, 'withPNI');
+        expectDeleted(withE164, 'withE164');
+
+        assert.strictEqual(result?.id, withACI?.id, 'result and withACI match');
+      });
+    });
+  });
+});
diff --git a/ts/test-electron/updateConversationsWithUuidLookup_test.ts b/ts/test-electron/updateConversationsWithUuidLookup_test.ts
index 763065711..48528f16b 100644
--- a/ts/test-electron/updateConversationsWithUuidLookup_test.ts
+++ b/ts/test-electron/updateConversationsWithUuidLookup_test.ts
@@ -27,15 +27,15 @@ describe('updateConversationsWithUuidLookup', () => {
       );
     }
 
-    ensureContactIds({
+    maybeMergeContacts({
       e164,
-      uuid: uuidFromServer,
-      highTrust,
+      aci: uuidFromServer,
+      reason,
     }: {
       e164?: string | null;
-      uuid?: string | null;
-      highTrust?: boolean;
-    }): string | undefined {
+      aci?: string | null;
+      reason?: string;
+    }): ConversationModel | undefined {
       assert(
         e164,
         'FakeConversationController is not set up for this case (E164 must be provided)'
@@ -45,8 +45,51 @@ describe('updateConversationsWithUuidLookup', () => {
         'FakeConversationController is not set up for this case (UUID must be provided)'
       );
       assert(
-        highTrust,
-        'FakeConversationController is not set up for this case (must be "high trust")'
+        reason,
+        'FakeConversationController must be provided a reason when merging'
+      );
+      const normalizedUuid = uuidFromServer!.toLowerCase();
+
+      const convoE164 = this.get(e164);
+      const convoUuid = this.get(normalizedUuid);
+      assert(
+        convoE164 || convoUuid,
+        'FakeConversationController is not set up for this case (at least one conversation should be found)'
+      );
+
+      if (convoE164 && convoUuid) {
+        if (convoE164 === convoUuid) {
+          return convoUuid;
+        }
+
+        convoE164.unset('e164');
+        convoUuid.updateE164(e164);
+        return convoUuid;
+      }
+
+      if (convoE164 && !convoUuid) {
+        convoE164.updateUuid(normalizedUuid);
+        return convoE164;
+      }
+
+      assert.fail('FakeConversationController should never get here');
+      return undefined;
+    }
+
+    lookupOrCreate({
+      e164,
+      uuid: uuidFromServer,
+    }: {
+      e164?: string | null;
+      uuid?: string | null;
+    }): string | undefined {
+      assert(
+        e164,
+        'FakeConversationController is not set up for this case (E164 must be provided)'
+      );
+      assert(
+        uuidFromServer,
+        'FakeConversationController is not set up for this case (UUID must be provided)'
       );
       const normalizedUuid = uuidFromServer!.toLowerCase();
 
@@ -62,13 +105,10 @@ describe('updateConversationsWithUuidLookup', () => {
           return convoUuid.get('id');
         }
 
-        convoE164.unset('e164');
-        convoUuid.updateE164(e164);
         return convoUuid.get('id');
       }
 
       if (convoE164 && !convoUuid) {
-        convoE164.updateUuid(normalizedUuid);
         return convoE164.get('id');
       }
 
@@ -218,7 +258,7 @@ describe('updateConversationsWithUuidLookup', () => {
     assert.isUndefined(conversation.get('discoveredUnregisteredAt'));
   });
 
-  it('marks conversations unregistered if we already had a UUID for them, even if the account does not exist on server', async () => {
+  it('marks conversations unregistered and removes UUID if the account does not exist on server', async () => {
     const existingUuid = UUID.generate().toString();
     const conversation = createConversation({
       e164: '+13215559876',
@@ -238,7 +278,7 @@ describe('updateConversationsWithUuidLookup', () => {
       messaging: fakeMessaging,
     });
 
-    assert.strictEqual(conversation.get('uuid'), existingUuid);
+    assert.isUndefined(conversation.get('uuid'));
     assert.isNumber(conversation.get('discoveredUnregisteredAt'));
   });
 });
diff --git a/ts/textsecure/AccountManager.ts b/ts/textsecure/AccountManager.ts
index 5128b5e08..24a3b8180 100644
--- a/ts/textsecure/AccountManager.ts
+++ b/ts/textsecure/AccountManager.ts
@@ -615,10 +615,9 @@ export default class AccountManager extends EventTarget {
     // This needs to be done very early, because it changes how things are saved in the
     //   database. Your identity, for example, in the saveIdentityWithAttributes call
     //   below.
-    const conversationId = window.ConversationController.ensureContactIds({
+    const conversationId = window.ConversationController.maybeMergeContacts({
+      aci: ourUuid,
       e164: number,
-      uuid: ourUuid,
-      highTrust: true,
       reason: 'createAccount',
     });
 
diff --git a/ts/types/StorageUIKeys.ts b/ts/types/StorageUIKeys.ts
index df7d12b10..a7e4cedc1 100644
--- a/ts/types/StorageUIKeys.ts
+++ b/ts/types/StorageUIKeys.ts
@@ -22,6 +22,7 @@ export const STORAGE_UI_KEYS: ReadonlyArray<keyof StorageAccessType> = [
   'incoming-call-notification',
   'notification-draw-attention',
   'notification-setting',
+  'pinnedConversationIds',
   'preferred-audio-input-device',
   'preferred-audio-output-device',
   'preferred-video-input-device',
diff --git a/ts/updateConversationsWithUuidLookup.ts b/ts/updateConversationsWithUuidLookup.ts
index 03eb2fde3..56c6e3432 100644
--- a/ts/updateConversationsWithUuidLookup.ts
+++ b/ts/updateConversationsWithUuidLookup.ts
@@ -15,7 +15,7 @@ export async function updateConversationsWithUuidLookup({
 }: Readonly<{
   conversationController: Pick<
     ConversationController,
-    'ensureContactIds' | 'get'
+    'maybeMergeContacts' | 'get'
   >;
   conversations: ReadonlyArray<ConversationModel>;
   messaging: Pick<SendMessage, 'getUuidsForE164s' | 'checkAccountExistence'>;
@@ -40,14 +40,12 @@ export async function updateConversationsWithUuidLookup({
 
       const uuidFromServer = getOwn(serverLookup, e164);
       if (uuidFromServer) {
-        const finalConversationId = conversationController.ensureContactIds({
-          e164,
-          uuid: uuidFromServer,
-          highTrust: true,
-          reason: 'updateConversationsWithUuidLookup',
-        });
         const maybeFinalConversation =
-          conversationController.get(finalConversationId);
+          conversationController.maybeMergeContacts({
+            aci: uuidFromServer,
+            e164,
+            reason: 'updateConversationsWithUuidLookup',
+          });
         assert(
           maybeFinalConversation,
           'updateConversationsWithUuidLookup: expected a conversation to be found or created'
diff --git a/ts/util/findStoryMessage.ts b/ts/util/findStoryMessage.ts
index c076292ec..3badd9671 100644
--- a/ts/util/findStoryMessage.ts
+++ b/ts/util/findStoryMessage.ts
@@ -68,14 +68,14 @@ function isStoryAMatch(
     return false;
   }
 
-  const authorConversationId = window.ConversationController.ensureContactIds({
+  const authorConversation = window.ConversationController.lookupOrCreate({
     e164: undefined,
     uuid: authorUuid,
   });
 
   return (
     message.sent_at === sentTimestamp &&
-    getContactId(message) === authorConversationId &&
+    getContactId(message) === authorConversation?.id &&
     (message.conversationId === conversationId ||
       message.conversationId === ourConversationId)
   );
diff --git a/ts/util/getProfile.ts b/ts/util/getProfile.ts
index bcece3048..013d2be16 100644
--- a/ts/util/getProfile.ts
+++ b/ts/util/getProfile.ts
@@ -4,15 +4,11 @@
 import * as log from '../logging/log';
 import { profileService } from '../services/profiles';
 
-export async function getProfile(
-  providedUuid?: string,
-  providedE164?: string
-): Promise<void> {
-  const id = window.ConversationController.ensureContactIds({
-    uuid: providedUuid,
-    e164: providedE164,
+export async function getProfile(uuid?: string, e164?: string): Promise<void> {
+  const c = window.ConversationController.lookupOrCreate({
+    uuid,
+    e164,
   });
-  const c = window.ConversationController.get(id);
   if (!c) {
     log.error('getProfile: failed to find conversation; doing nothing');
     return;
diff --git a/ts/util/handleRetry.ts b/ts/util/handleRetry.ts
index 495c1fa88..f7bbb31ea 100644
--- a/ts/util/handleRetry.ts
+++ b/ts/util/handleRetry.ts
@@ -616,18 +616,9 @@ function startAutomaticSessionReset(decryptionError: DecryptionErrorEventData) {
 
   scheduleSessionReset(senderUuid, senderDevice);
 
-  const conversationId = window.ConversationController.ensureContactIds({
+  const conversation = window.ConversationController.lookupOrCreate({
     uuid: senderUuid,
   });
-
-  if (!conversationId) {
-    log.warn(
-      'onLightSessionReset: No conversation id, cannot add message to timeline'
-    );
-    return;
-  }
-  const conversation = window.ConversationController.get(conversationId);
-
   if (!conversation) {
     log.warn(
       'onLightSessionReset: No conversation, cannot add message to timeline'
diff --git a/ts/util/lookupConversationWithoutUuid.ts b/ts/util/lookupConversationWithoutUuid.ts
index 1d6904994..36af8d1e7 100644
--- a/ts/util/lookupConversationWithoutUuid.ts
+++ b/ts/util/lookupConversationWithoutUuid.ts
@@ -73,25 +73,24 @@ export async function lookupConversationWithoutUuid(
       const serverLookup = await messaging.getUuidsForE164s([options.e164]);
 
       if (serverLookup[options.e164]) {
-        conversationId = window.ConversationController.ensureContactIds({
+        const convo = window.ConversationController.maybeMergeContacts({
+          aci: serverLookup[options.e164] || undefined,
           e164: options.e164,
-          uuid: serverLookup[options.e164],
-          highTrust: true,
           reason: 'startNewConversationWithoutUuid(e164)',
         });
+        conversationId = convo?.id;
       }
     } else {
       const foundUsername = await checkForUsername(options.username);
       if (foundUsername) {
-        conversationId = window.ConversationController.ensureContactIds({
+        const convo = window.ConversationController.lookupOrCreate({
           uuid: foundUsername.uuid,
-          highTrust: true,
-          reason: 'startNewConversationWithoutUuid(username)',
         });
 
-        const convo = window.ConversationController.get(conversationId);
         strictAssert(convo, 'We just ensured conversation existence');
 
+        conversationId = convo.id;
+
         convo.set({ username: foundUsername.username });
       }
     }
diff --git a/ts/util/markConversationRead.ts b/ts/util/markConversationRead.ts
index f132d3de1..86bc964b3 100644
--- a/ts/util/markConversationRead.ts
+++ b/ts/util/markConversationRead.ts
@@ -89,10 +89,10 @@ export async function markConversationRead(
       originalReadStatus: messageSyncData.originalReadStatus,
       senderE164: messageSyncData.source,
       senderUuid: messageSyncData.sourceUuid,
-      senderId: window.ConversationController.ensureContactIds({
+      senderId: window.ConversationController.lookupOrCreate({
         e164: messageSyncData.source,
         uuid: messageSyncData.sourceUuid,
-      }),
+      })?.id,
       timestamp: messageSyncData.sent_at,
       hasErrors: message ? hasErrors(message.attributes) : false,
     };
diff --git a/ts/util/sendReceipts.ts b/ts/util/sendReceipts.ts
index 71307b3e7..fe53fbec2 100644
--- a/ts/util/sendReceipts.ts
+++ b/ts/util/sendReceipts.ts
@@ -63,21 +63,21 @@ export async function sendReceipts({
         return result;
       }
 
-      const senderId = window.ConversationController.ensureContactIds({
+      const sender = window.ConversationController.lookupOrCreate({
         e164: senderE164,
         uuid: senderUuid,
       });
-      if (!senderId) {
+      if (!sender) {
         throw new Error(
           'no conversation found with that E164/UUID. Cannot send this receipt'
         );
       }
 
-      const existingGroup = result.get(senderId);
+      const existingGroup = result.get(sender.id);
       if (existingGroup) {
         existingGroup.push(receipt);
       } else {
-        result.set(senderId, [receipt]);
+        result.set(sender.id, [receipt]);
       }
 
       return result;
diff --git a/ts/views/conversation_view.tsx b/ts/views/conversation_view.tsx
index 55ff21fb3..132137c5a 100644
--- a/ts/views/conversation_view.tsx
+++ b/ts/views/conversation_view.tsx
@@ -1354,12 +1354,10 @@ export class ConversationView extends window.Backbone.View<ConversationModel> {
                 message: {
                   attachments: message.attachments || [],
                   conversationId:
-                    window.ConversationController.get(
-                      window.ConversationController.ensureContactIds({
-                        uuid: message.sourceUuid,
-                        e164: message.source,
-                      })
-                    )?.id || message.conversationId,
+                    window.ConversationController.lookupOrCreate({
+                      uuid: message.sourceUuid,
+                      e164: message.source,
+                    })?.id || message.conversationId,
                   id: message.id,
                   received_at: message.received_at,
                   received_at_ms: Number(message.received_at_ms),
@@ -1816,12 +1814,10 @@ export class ConversationView extends window.Backbone.View<ConversationModel> {
           attachments: message.get('attachments') || [],
           id: message.get('id'),
           conversationId:
-            window.ConversationController.get(
-              window.ConversationController.ensureContactIds({
-                uuid: message.get('sourceUuid'),
-                e164: message.get('source'),
-              })
-            )?.id || message.get('conversationId'),
+            window.ConversationController.lookupOrCreate({
+              uuid: message.get('sourceUuid'),
+              e164: message.get('source'),
+            })?.id || message.get('conversationId'),
           received_at: message.get('received_at'),
           received_at_ms: Number(message.get('received_at_ms')),
           sent_at: message.get('sent_at'),
@@ -2116,16 +2112,16 @@ export class ConversationView extends window.Backbone.View<ConversationModel> {
   }
 
   startConversation(e164: string, uuid: UUIDStringType): void {
-    const conversationId = window.ConversationController.ensureContactIds({
+    const conversation = window.ConversationController.lookupOrCreate({
       e164,
       uuid,
     });
     strictAssert(
-      conversationId,
+      conversation,
       `startConversation failed given ${e164}/${uuid} combination`
     );
 
-    this.openConversation(conversationId);
+    this.openConversation(conversation.id);
   }
 
   async openConversation(