diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,4 +1,7 @@
 2024-01-07
+        * Version bump (3.18.1). (#493)
+
+2024-01-07
         * Version bump (3.18). (#487)
         * Introduce testing infrastructure for Copilot.Library. (#475)
         * Replace uses of forall with forAll. (#470)
diff --git a/copilot-libraries.cabal b/copilot-libraries.cabal
--- a/copilot-libraries.cabal
+++ b/copilot-libraries.cabal
@@ -1,6 +1,6 @@
 cabal-version:       >=1.10
 name:                copilot-libraries
-version:             3.18
+version:             3.18.1
 synopsis:            Libraries for the Copilot language.
 description:
   Libraries for the Copilot language.
@@ -41,7 +41,7 @@
                , containers       >= 0.4 && < 0.7
                , mtl              >= 2.0 && < 2.4
                , parsec           >= 2.0 && < 3.2
-               , copilot-language >= 3.18 && < 3.19
+               , copilot-language >= 3.18.1 && < 3.19
 
   exposed-modules:
       Copilot.Library.Libraries