diff --git a/midi.cabal b/midi.cabal
--- a/midi.cabal
+++ b/midi.cabal
@@ -1,5 +1,5 @@
 Name:             midi
-Version:          0.2.2
+Version:          0.2.2.1
 License:          GPL
 License-File:     LICENSE
 Author:           Henning Thielemann <haskell@henning-thielemann.de>
@@ -30,7 +30,7 @@
 Source-Repository this
   type:     darcs
   location: http://hub.darcs.net/thielema/midi/
-  tag:      0.2.2
+  tag:      0.2.2.1
 
 Flag splitBase
   description: Choose the new smaller, split-up base package.
@@ -42,8 +42,8 @@
     utility-ht >=0.0.10 && <0.1,
     explicit-exception >=0.1 && <0.2,
     bytestring >=0.9.0.1 && <0.11,
-    binary >=0.4.2 && <0.8,
-    transformers >=0.2 && <0.5,
+    binary >=0.4.2 && <0.9,
+    transformers >=0.2 && <0.6,
     monoid-transformer >=0.0.1 && <0.1,
     QuickCheck >=2.1 && <3
   If flag(splitBase)
diff --git a/src/Sound/MIDI/Message.hs b/src/Sound/MIDI/Message.hs
--- a/src/Sound/MIDI/Message.hs
+++ b/src/Sound/MIDI/Message.hs
@@ -34,6 +34,8 @@
 data T =
      Channel Channel.T
    | System  System.T
+-- Show instance requires Show instance of System.T
+--     deriving (Show)
 
 
 get :: Parser.C parser => Parser.Fragile parser T
diff --git a/src/Sound/MIDI/Message/Channel.hs b/src/Sound/MIDI/Message/Channel.hs
--- a/src/Sound/MIDI/Message/Channel.hs
+++ b/src/Sound/MIDI/Message/Channel.hs
@@ -40,6 +40,7 @@
      messageChannel :: Channel,
      messageBody    :: Body
    }
+     -- ToDo: make nicer Show instance
      deriving (Show, Eq, Ord)
 
 data Body =
diff --git a/src/Sound/MIDI/Monoid.hs b/src/Sound/MIDI/Monoid.hs
--- a/src/Sound/MIDI/Monoid.hs
+++ b/src/Sound/MIDI/Monoid.hs
@@ -21,6 +21,7 @@
 genConcat cons decons =
    cons . concatMap decons
 
+-- foldMap
 concatMap :: (Monoid m) =>
    (a -> m) -> [a] -> m
 concatMap f = mconcat . map f