diff --git a/nixos/doc/manual/from_md/release-notes/rl-2205.section.xml b/nixos/doc/manual/from_md/release-notes/rl-2205.section.xml
index 85809fbed892..ad290f13821f 100644
--- a/nixos/doc/manual/from_md/release-notes/rl-2205.section.xml
+++ b/nixos/doc/manual/from_md/release-notes/rl-2205.section.xml
@@ -2444,6 +2444,14 @@ cp /var/lib/redis/dump.rdb "/var/lib/redis-mastodon/dump.rdb"
           desktop environments as needed.
         </para>
       </listitem>
+      <listitem>
+        <para>
+          <literal>mercury</literal> was updated to 22.01.1, which has
+          some breaking changes
+          (<link xlink:href="https://dl.mercurylang.org/release/release-notes-22.01.html">Mercury
+          22.01 news</link>).
+        </para>
+      </listitem>
       <listitem>
         <para>
           xfsprogs was update to version 5.15, which enables inobtcount
diff --git a/nixos/doc/manual/release-notes/rl-2205.section.md b/nixos/doc/manual/release-notes/rl-2205.section.md
index 3f7bc913f0c5..8daa515cee7a 100644
--- a/nixos/doc/manual/release-notes/rl-2205.section.md
+++ b/nixos/doc/manual/release-notes/rl-2205.section.md
@@ -874,6 +874,8 @@ In addition to numerous new and upgraded packages, this release has the followin
 
 - The polkit service, available at `security.polkit.enable`, is now disabled by default. It will automatically be enabled through services and desktop environments as needed.
 
+- `mercury` was updated to 22.01.1, which has some breaking changes ([Mercury 22.01 news](https://dl.mercurylang.org/release/release-notes-22.01.html)).
+
 - xfsprogs was update to version 5.15, which enables inobtcount and bigtime by default on filesystem creation. Support for these features was added in kernel 5.10 and deemed stable in kernel 5.15.
   If you want to be able to mount XFS filesystems created with this release of xfsprogs on kernel releases older than 5.10, you need to format them with `mkfs.xfs -m bigtime=0 -m inobtcount=0`.
 
diff --git a/pkgs/development/compilers/mercury/default.nix b/pkgs/development/compilers/mercury/default.nix
index c5e767a46cde..ef1468ac1ed9 100644
--- a/pkgs/development/compilers/mercury/default.nix
+++ b/pkgs/development/compilers/mercury/default.nix
@@ -3,11 +3,11 @@
 
 stdenv.mkDerivation rec {
   pname = "mercury";
-  version = "20.06.1";
+  version = "22.01.1";
 
   src = fetchurl {
     url    = "https://dl.mercurylang.org/release/mercury-srcdist-${version}.tar.gz";
-    sha256 = "ef093ae81424c4f3fe696eff9aefb5fb66899e11bb17ae0326adfb70d09c1c1f";
+    sha256 = "sha256-Cg0ixQtpmus6Q3fuc45OLheKCCTiTW3z1XJzxQ1OL6c=";
   };
 
   nativeBuildInputs = [ makeWrapper ];