diff --git a/pkgs/development/tools/icr/default.nix b/pkgs/development/tools/icr/default.nix
index 13c4cbe37db8..ca052c0f210a 100644
--- a/pkgs/development/tools/icr/default.nix
+++ b/pkgs/development/tools/icr/default.nix
@@ -1,15 +1,26 @@
-{ stdenv, lib, fetchFromGitHub, crystal, shards, makeWrapper, pkg-config, which
-, openssl, readline, libyaml, zlib }:
+{ stdenv
+, lib
+, fetchFromGitHub
+, crystal
+, shards
+, makeWrapper
+, pkg-config
+, which
+, openssl
+, readline
+, libyaml
+, zlib
+}:
 
 crystal.buildCrystalPackage rec {
   pname = "icr";
-  version = "0.8.0";
+  version = "unstable-2020-10-06";
 
   src = fetchFromGitHub {
     owner = "crystal-community";
-    repo = pname;
-    rev = "v${version}";
-    sha256 = "1bz2bhs6csyg2rhrlknlvaiilq3vq8plxjh1hdxmbrfi3n6c7k5a";
+    repo = "icr";
+    rev = "8c57cd7c1fdf8088cb05c1587bd6c40d244a8a80";
+    sha256 = "sha256-b0w6oG2npNgdi2ZowMlJy0iUxQWqb9+DiruQl7Ztb0E=";
   };
 
   shardsFile = ./shards.nix;