diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+# log-base-0.9.1.1 (2021-05-28)
+* Support GHC 9.0.
+
 # log-base-0.9.1.0 (2021-03-01)
 * Add a `LogList` logger
 
diff --git a/log-base.cabal b/log-base.cabal
--- a/log-base.cabal
+++ b/log-base.cabal
@@ -1,5 +1,5 @@
 name:                log-base
-version:             0.9.1.0
+version:             0.9.1.1
 synopsis:            Structured logging solution (base package)
 
 description:         A library that provides a way to record structured log
@@ -22,6 +22,7 @@
 cabal-version:       >=1.10
 extra-source-files:  CHANGELOG.md, README.md
 tested-with:         GHC ==8.0.2 || ==8.2.2 || ==8.4.4 || ==8.6.5 || ==8.8.4 || ==8.10.4
+                      || ==9.0.1
 
 Source-repository head
   Type:     git
diff --git a/src/Log/Monad.hs b/src/Log/Monad.hs
--- a/src/Log/Monad.hs
+++ b/src/Log/Monad.hs
@@ -107,7 +107,7 @@
 --
 -- @since 0.7.2
 instance MFunctor LogT where
-    hoist = mapLogT
+    hoist f = mapLogT f
 
 instance MonadTransControl LogT where
 #if MIN_VERSION_monad_control(1,0,0)