diff --git a/copilot-theorem/copilot-theorem.cabal b/copilot-theorem/copilot-theorem.cabal
index c6994913f..22339f264 100644
--- a/copilot-theorem/copilot-theorem.cabal
+++ b/copilot-theorem/copilot-theorem.cabal
@@ -61,7 +61,7 @@ library
                           , random                >= 1.1 && < 1.3
                           , transformers          >= 0.5 && < 0.7
                           , xml                   >= 1.3 && < 1.4
-                          , what4                 >= 1.3 && < 1.7
+                          , what4                 >= 1.3 && < 1.8
 
                           , copilot-core          >= 4.3 && < 4.4
                           , copilot-prettyprinter >= 4.3 && < 4.4