diff --git a/equal-files.cabal b/equal-files.cabal
--- a/equal-files.cabal
+++ b/equal-files.cabal
@@ -1,5 +1,5 @@
 Name:           equal-files
-Version:        0.0.5.3
+Version:        0.0.5.4
 License:        GPL
 License-File:   LICENSE
 Author:         Henning Thielemann <haskell@henning-thielemann.de>
@@ -40,11 +40,11 @@
    that is enabled by lazy evaluation.
 -- Stability:      Experimental
 Tested-With:    GHC==6.8.2
-Cabal-Version:  >=1.6
+Cabal-Version:  >=1.10
 Build-Type:     Simple
 
 Source-Repository this
-  Tag:         0.0.5.3
+  Tag:         0.0.5.4
   Type:        darcs
   Location:    http://code.haskell.org/~thielema/equal-files/
 
@@ -55,12 +55,13 @@
 Executable equal-files
   Build-Depends:
     filemanip >=0.3.5 && <0.4,
-    explicit-exception >=0.1 && <0.2,
-    transformers >=0.2 && <0.6,
+    explicit-exception >=0.1 && <0.3,
+    transformers >=0.2 && <0.7,
     utility-ht >=0.0.1 && <0.1,
-    bytestring >=0.9 && <0.11,
+    bytestring >=0.9 && <0.12,
     base >=3 && <5
 
+  Default-Language: Haskell98
   GHC-Options:    -Wall
   Hs-source-dirs: src
   Other-Modules:  EqualFiles
diff --git a/src/Main.hs b/src/Main.hs
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -79,6 +79,8 @@
              (usageInfo ("Usage: " ++ programName ++ " [OPTIONS] FILES-AND-DIRECTORIES ...") options) >>
           exitWith ExitSuccess)
 
+      -- ToDo: speed up by pre-sorting with respect to file size
+      -- ToDo: save memory by converting filepaths to Text
       files <-
          if optRecursive flags
            then lift $ liftM concat $