diff --git a/automaton.cabal b/automaton.cabal
--- a/automaton.cabal
+++ b/automaton.cabal
@@ -1,6 +1,6 @@
 cabal-version: 3.0
 name: automaton
-version: 1.6
+version: 1.6.1
 synopsis: Effectful streams and automata in coalgebraic encoding
 description:
   Effectful streams have an internal state and a step function.
@@ -30,7 +30,7 @@
   build-depends:
     MonadRandom >=0.5,
     base >=4.16 && <4.22,
-    changeset ^>=0.1.0.2,
+    changeset ^>=0.1.1,
     mmorph ^>=1.2,
     mtl >=2.2 && <2.4,
     profunctors ^>=5.6,
diff --git a/test/Automaton/Trans/Changeset.hs b/test/Automaton/Trans/Changeset.hs
--- a/test/Automaton/Trans/Changeset.hs
+++ b/test/Automaton/Trans/Changeset.hs
@@ -16,9 +16,5 @@
 -- automaton
 import Data.Automaton
 import Data.Automaton.Trans.Changeset (runChangesetS)
-import Data.Monoid.RightAction (RightAction (actRight))
 
 tests = testGroup "Trans.Changeset" [testCase "runChangesetS" $ runIdentity (embed (runChangesetS (Sum (0 :: Int)) (constM (change (Sum (1 :: Int)) >> current))) (replicate 5 ())) @?= (\n -> (n, n)) <$> [1, 2, 3, 4, 5]]
-
-instance (Num a) => RightAction (Sum a) (Sum a) where
-  a1 `actRight` a2 = a1 <> a2