diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,7 @@
+2026-09-07
+        * Version bump (4.8.1). (#760)
+        * Remove unnecessary extension. (#733)
+
 2026-07-07
         * Version bump (4.8). (#745)
         * Extend range of versions of Kind2. (#734)
diff --git a/copilot-theorem.cabal b/copilot-theorem.cabal
--- a/copilot-theorem.cabal
+++ b/copilot-theorem.cabal
@@ -14,7 +14,7 @@
   <https://copilot-language.github.io>.
 
 
-version                   : 4.8
+version                   : 4.8.1
 license                   : BSD3
 license-file              : LICENSE
 maintainer                : Ivan Perez <ivan.perezdominguez@nasa.gov>
@@ -63,8 +63,8 @@
                           , transformers          >= 0.5 && < 0.7
                           , what4                 >= 1.3 && < 1.8
 
-                          , copilot-core          >= 4.8 && < 4.9
-                          , copilot-prettyprinter >= 4.8 && < 4.9
+                          , copilot-core          >= 4.8.1 && < 4.9
+                          , copilot-prettyprinter >= 4.8.1 && < 4.9
 
   exposed-modules         : Copilot.Theorem
                           , Copilot.Theorem.Prove
diff --git a/src/Copilot/Theorem/What4/Translate.hs b/src/Copilot/Theorem/What4/Translate.hs
--- a/src/Copilot/Theorem/What4/Translate.hs
+++ b/src/Copilot/Theorem/What4/Translate.hs
@@ -2,7 +2,6 @@
 {-# LANGUAGE FlexibleContexts           #-}
 {-# LANGUAGE GADTs                      #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
-{-# LANGUAGE PatternSynonyms            #-}
 {-# LANGUAGE RankNTypes                 #-}
 {-# LANGUAGE ScopedTypeVariables        #-}
 {-# LANGUAGE StandaloneDeriving         #-}