diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,15 @@
+1.2.2
+-----
+* Relaxed upper version bound for `transformers`.
+
+1.2.1
+-----
+* Explicitly mark `Data.StateVar` as Safe (or Trustworthy for GHC before 7.10).
+
+1.2
+---
+* Added instances for `ForeignPtr`.
+
 1.1.1.1
 -------
 * Relaxed upper version bound for `stm`.
diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,5 +1,5 @@
 Copyright (c) 2014-2015, Edward Kmett
-Copyright (c) 2009-2018, Sven Panne
+Copyright (c) 2009-2021, Sven Panne
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
diff --git a/StateVar.cabal b/StateVar.cabal
--- a/StateVar.cabal
+++ b/StateVar.cabal
@@ -1,12 +1,12 @@
 name: StateVar
-version: 1.1.1.1
+version: 1.2.2
 synopsis: State variables
 description:
   This package contains state variables, which are references in the IO monad,
   like IORefs or parts of the OpenGL state.
 homepage: https://github.com/haskell-opengl/StateVar
 bug-reports: https://github.com/haskell-opengl/StateVar/issues
-copyright: Copyright (C) 2014-2015 Edward A. Kmett, 2009-2018 Sven Panne
+copyright: Copyright (C) 2014-2015 Edward A. Kmett, 2009-2021 Sven Panne
 license: BSD3
 license-file: LICENSE
 author: Sven Panne and Edward Kmett
@@ -23,8 +23,11 @@
   GHC == 8.0.2
   GHC == 8.2.2
   GHC == 8.4.3
-  GHC == 8.6.1
-  GHC == 8.7.*
+  GHC == 8.6.5
+  GHC == 8.8.4
+  GHC == 8.10.3
+  GHC == 8.10.4
+  GHC == 9.0.1
 cabal-version: >= 1.10
 extra-source-files:
   README.md
@@ -36,8 +39,8 @@
 
   build-depends:
     base         >= 4   && < 5,
-    stm          >= 2.2.0.1 && < 2.6,
-    transformers >= 0.2 && < 0.6
+    stm          >= 2.3.0.1 && < 2.6,
+    transformers >= 0.3 && < 0.7
 
   default-language: Haskell2010
   other-extensions:
@@ -55,6 +58,11 @@
   if impl(ghc>=7.4)
     -- other-extensions: DefaultSignatures
     cpp-options: -DUSE_DEFAULT_SIGNATURES=1
+
+  if impl(ghc >= 9.0)
+    -- these flags may abort compilation with GHC-8.10
+    -- https://gitlab.haskell.org/ghc/ghc/-/merge_requests/3295
+    ghc-options: -Winferred-safe-imports -Wmissing-safe-haskell-mode
 
 source-repository head
   type: git
diff --git a/src/Data/StateVar.hs b/src/Data/StateVar.hs
--- a/src/Data/StateVar.hs
+++ b/src/Data/StateVar.hs
@@ -7,10 +7,16 @@
 {-# LANGUAGE DefaultSignatures #-}
 #endif
 {-# LANGUAGE TypeFamilies #-}
+-- Foreign.ForeignPtr is unsafe before GHC-7.10
+#if __GLASGOW_HASKELL__ >= 704 && MIN_VERSION_base(4,8,0)
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
 --------------------------------------------------------------------------------
 -- |
 -- Module      :  Data.StateVar
--- Copyright   :  (c) Edward Kmett 2014-2015, Sven Panne 2009-2018
+-- Copyright   :  (c) Edward Kmett 2014-2019, Sven Panne 2009-2021
 -- License     :  BSD3
 -- 
 -- Maintainer  :  Sven Panne <svenpanne@gmail.com>
@@ -81,6 +87,7 @@
 import Control.Monad.IO.Class
 import Data.IORef
 import Data.Typeable
+import Foreign.ForeignPtr
 import Foreign.Ptr
 import Foreign.Storable
 #if MIN_VERSION_base(4,12,0)
@@ -195,6 +202,10 @@
   p $= a = liftIO $ atomically $ writeTVar p a
   {-# INLINE ($=) #-}
 
+instance Storable a => HasSetter (ForeignPtr a) a where
+  p $= a = liftIO $ withForeignPtr p ($= a)
+  {-# INLINE ($=) #-}
+
 --------------------------------------------------------------------
 -- * HasUpdate
 --------------------------------------------------------------------
@@ -252,6 +263,10 @@
     a <- readTVar r
     writeTVar r $! f a
 
+instance Storable a => HasUpdate (ForeignPtr a) a a where
+  p $~ f = liftIO $ withForeignPtr p ($~ f)
+  p $~! f = liftIO $ withForeignPtr p ($~! f)
+
 --------------------------------------------------------------------
 -- * HasGetter
 --------------------------------------------------------------------
@@ -283,3 +298,8 @@
 instance HasGetter (IORef a) a where
   get = liftIO . readIORef
   {-# INLINE get #-}
+
+instance Storable a => HasGetter (ForeignPtr a) a where
+  get p = liftIO $ withForeignPtr p get
+  {-# INLINE get #-}
+