diff --git a/pkgs/development/compilers/unison/default.nix b/pkgs/development/compilers/unison/default.nix
index 2a8c07fa0fe0..c24786cd9a04 100644
--- a/pkgs/development/compilers/unison/default.nix
+++ b/pkgs/development/compilers/unison/default.nix
@@ -4,18 +4,18 @@
 
 stdenv.mkDerivation rec {
   pname = "unison-code-manager";
-  milestone_id = "M1g";
+  milestone_id = "M1h";
   version = "1.0.${milestone_id}-alpha";
 
   src = if (stdenv.isDarwin) then
     fetchurl {
       url = "https://github.com/unisonweb/unison/releases/download/release/${milestone_id}/unison-osx.tar.gz";
-      sha256 = "186y7y7ffg976w01cbb8am84ajbifb7lcnsc4g3x262mkswr7lry";
+      sha256 = "0iivm5gmbk0fq0zr3lvck6p1c2i7i54l3rf70z677529w9irzchp";
     }
   else
     fetchurl {
       url = "https://github.com/unisonweb/unison/releases/download/release/${milestone_id}/unison-linux64.tar.gz";
-      sha256 = "1ki9car1clpaspnl5jb5qnr6nzv108q279n8m8bjm8azfcnl61ab";
+      sha256 = "0fb84c1yn8pidflh7kq696j3v4blkvbk1fsqp36h30p7vv676yci";
     };
 
   # The tarball is just the prebuilt binary, in the archive root.