diff --git a/Reactor/InfoBus.hs b/Reactor/InfoBus.hs
--- a/Reactor/InfoBus.hs
+++ b/Reactor/InfoBus.hs
@@ -12,6 +12,7 @@
    ) where
 
 
+import Control.Exception
 import Control.Concurrent.MVar
 import qualified Data.Map as Map
 import System.IO.Unsafe
@@ -70,7 +71,7 @@
          do
             map <- takeMVar toolmanager
             putMVar toolmanager (Map.delete oid map)
-         )
+         ) :: IO (Either SomeException ())
       debug ("deregisterTool ",oid)
       done
 
@@ -84,7 +85,7 @@
          (\ (oid,cmd) ->
             do
                debug ("Shutting down ",oid)
-               try cmd
+               try cmd :: IO (Either SomeException ())
             )
       performGC
 
diff --git a/uni-reactor.cabal b/uni-reactor.cabal
--- a/uni-reactor.cabal
+++ b/uni-reactor.cabal
@@ -1,5 +1,5 @@
 name:           uni-reactor
-version:        2.2.0.0
+version:        2.2.1.0
 build-type:     Simple
 license:        LGPL
 license-file:   LICENSE
@@ -10,7 +10,7 @@
 synopsis:       Reactors for the uniform workbench
 description:    uni reactor
 cabal-version:  >= 1.4
-Tested-With:    GHC==6.8.3, GHC==6.10.4, GHC==6.12.3
+Tested-With:    GHC==6.10.4, GHC==6.12.3
 
 library
   exposed-modules:
@@ -21,7 +21,6 @@
     Reactor.InfoBus,
     Reactor.WithDir
 
-  build-depends: base >=3 && < 5, containers, directory, uni-util, uni-events
+  build-depends: base >=4 && < 5, containers, directory, uni-util, uni-events
 
-  if impl(ghc > 6.10)
-    ghc-options: -fwarn-unused-imports -fno-warn-warnings-deprecations
+  ghc-options: -fwarn-unused-imports -fno-warn-warnings-deprecations