diff --git a/acid-state.cabal b/acid-state.cabal
--- a/acid-state.cabal
+++ b/acid-state.cabal
@@ -7,7 +7,7 @@
 -- The package version. See the Haskell package versioning policy
 -- (http://www.haskell.org/haskellwiki/Package_versioning_policy) for
 -- standards guiding when and how versions should be incremented.
-Version:             0.3
+Version:             0.3.1
 
 -- A short (one-line) description of the package.
 Synopsis:            Add ACID guarantees to any serializable Haskell data structure.
diff --git a/src/Data/Acid.hs b/src/Data/Acid.hs
--- a/src/Data/Acid.hs
+++ b/src/Data/Acid.hs
@@ -4,7 +4,7 @@
  Copyright   :  PublicDomain
 
  Maintainer  :  lemmih@gmail.com
- Portability :  portable
+ Portability :  non-portable (uses GHC extensions)
 
  AcidState container using a transaction log on disk.
 
diff --git a/src/Data/Acid/Core.hs b/src/Data/Acid/Core.hs
--- a/src/Data/Acid/Core.hs
+++ b/src/Data/Acid/Core.hs
@@ -6,7 +6,7 @@
 -- Copyright   :  PublicDomain
 --
 -- Maintainer  :  lemmih@gmail.com
--- Portability :  portable
+-- Portability :  non-portable (uses GHC extensions)
 --
 -- Low-level controls for transaction-based state changes. This module defines
 -- structures and tools for running state modifiers indexed either by an Method
diff --git a/src/Data/Acid/Local.hs b/src/Data/Acid/Local.hs
--- a/src/Data/Acid/Local.hs
+++ b/src/Data/Acid/Local.hs
@@ -6,7 +6,7 @@
 -- Copyright   :  PublicDomain
 --
 -- Maintainer  :  lemmih@gmail.com
--- Portability :  portable
+-- Portability :  non-portable (uses GHC extensions)
 --
 -- AcidState container using a transaction log on disk. The term \'Event\' is
 -- loosely used for transactions with ACID guarantees. \'Method\' is loosely