diff --git a/Control/Concurrent/Broadcast.hs b/Control/Concurrent/Broadcast.hs
--- a/Control/Concurrent/Broadcast.hs
+++ b/Control/Concurrent/Broadcast.hs
@@ -1,5 +1,9 @@
 {-# LANGUAGE CPP, DeriveDataTypeable, NoImplicitPrelude, UnicodeSyntax #-}
 
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Safe #-}
+#endif
+
 -------------------------------------------------------------------------------
 -- |
 -- Module     : Control.Concurrent.Broadcast
diff --git a/Control/Concurrent/Event.hs b/Control/Concurrent/Event.hs
--- a/Control/Concurrent/Event.hs
+++ b/Control/Concurrent/Event.hs
@@ -4,6 +4,10 @@
            , UnicodeSyntax
   #-}
 
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Safe #-}
+#endif
+
 -------------------------------------------------------------------------------
 -- |
 -- Module     : Control.Concurrent.Event
diff --git a/Control/Concurrent/Lock.hs b/Control/Concurrent/Lock.hs
--- a/Control/Concurrent/Lock.hs
+++ b/Control/Concurrent/Lock.hs
@@ -1,5 +1,9 @@
 {-# LANGUAGE CPP, DeriveDataTypeable, NoImplicitPrelude, UnicodeSyntax #-}
 
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Safe #-}
+#endif
+
 --------------------------------------------------------------------------------
 -- |
 -- Module     : Control.Concurrent.Lock
diff --git a/Control/Concurrent/RLock.hs b/Control/Concurrent/RLock.hs
--- a/Control/Concurrent/RLock.hs
+++ b/Control/Concurrent/RLock.hs
@@ -5,6 +5,10 @@
            , UnicodeSyntax
   #-}
 
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Safe #-}
+#endif
+
 --------------------------------------------------------------------------------
 -- |
 -- Module     : Control.Concurrent.RLock
diff --git a/Control/Concurrent/ReadWriteLock.hs b/Control/Concurrent/ReadWriteLock.hs
--- a/Control/Concurrent/ReadWriteLock.hs
+++ b/Control/Concurrent/ReadWriteLock.hs
@@ -5,6 +5,10 @@
            , UnicodeSyntax
   #-}
 
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Safe #-}
+#endif
+
 -------------------------------------------------------------------------------
 -- |
 -- Module     : Control.Concurrent.ReadWriteLock
diff --git a/Control/Concurrent/ReadWriteVar.hs b/Control/Concurrent/ReadWriteVar.hs
--- a/Control/Concurrent/ReadWriteVar.hs
+++ b/Control/Concurrent/ReadWriteVar.hs
@@ -5,6 +5,10 @@
            , UnicodeSyntax
   #-}
 
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Safe #-}
+#endif
+
 -------------------------------------------------------------------------------
 -- |
 -- Module     : Control.Concurrent.ReadWriteVar
diff --git a/Control/Concurrent/STM/Lock.hs b/Control/Concurrent/STM/Lock.hs
--- a/Control/Concurrent/STM/Lock.hs
+++ b/Control/Concurrent/STM/Lock.hs
@@ -1,5 +1,9 @@
 {-# LANGUAGE CPP, DeriveDataTypeable, NoImplicitPrelude, UnicodeSyntax #-}
 
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 --------------------------------------------------------------------------------
 -- |
 -- Module     : Control.Concurrent.STM.Lock
diff --git a/concurrent-extra.cabal b/concurrent-extra.cabal
--- a/concurrent-extra.cabal
+++ b/concurrent-extra.cabal
@@ -1,5 +1,5 @@
 name:          concurrent-extra
-version:       0.7.0.2
+version:       0.7.0.3
 cabal-version: >= 1.8
 build-type:    Custom
 stability:     experimental