diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,8 @@
+2024-08-21 Ivan Perez <ivan.perez@keera.co.uk>
+        * Version bump (0.13.1) (#430).
+        * Increase upper bounds on transformers (#427).
+        * Thanks to @tomsmeding.
+
 2024-06-21 Ivan Perez <ivan.perez@keera.co.uk>
         * Version bump (0.13.0) (#420).
         * Implement List interface using list-transformer (#418).
diff --git a/dunai.cabal b/dunai.cabal
--- a/dunai.cabal
+++ b/dunai.cabal
@@ -30,7 +30,7 @@
 build-type:    Simple
 
 name:          dunai
-version:       0.13.0
+version:       0.13.1
 author:        Ivan Perez, Manuel Bärenz
 maintainer:    ivan.perez@keera.co.uk
 homepage:      https://github.com/ivanperez-keera/dunai
@@ -133,7 +133,6 @@
       base >= 4.6 && < 5
     , MonadRandom         >= 0.2 && < 0.7
     , simple-affine-space >= 0.2 && < 0.3
-    , transformers        >= 0.3 && < 0.6
     , transformers-base   >= 0.4 && < 0.5
 
   default-language:
@@ -151,12 +150,16 @@
       , transformers-compat >= 0.3 && < 0.8
       , void                >= 0.1 && < 0.8
 
+  -- The upper bound on transformers depends on whether this flag is set
   if flag(list-transformer)
     build-depends:
         list-transformer >= 1.1.1 && < 1.2
       , transformers     >= 0.3   && < 0.7
 
     cpp-options: -DLIST_TRANSFORMER
+  else
+    build-depends:
+        transformers     >= 0.3   && < 0.6
 
 test-suite hlint
   type:
@@ -226,7 +229,7 @@
 
   build-depends:
       base         >= 4   && < 5
-    , transformers >= 0.3 && < 0.6
+    , transformers >= 0.3 && < 0.7
     , tasty        >= 0.1 && < 1.5
     , tasty-hunit  >= 0.8 && < 0.11