diff --git a/Trace/Hpc/Mix.hs b/Trace/Hpc/Mix.hs
--- a/Trace/Hpc/Mix.hs
+++ b/Trace/Hpc/Mix.hs
@@ -14,15 +14,13 @@
         , CondBox(..)
         , mixCreate
         , readMix
-        , Trace.Hpc.Mix.getModificationTime
         , createMixEntryDom
         , MixEntryDom
         )
   where
 
-import System.Time (ClockTime(..))
-import System.Directory (getModificationTime)
 import Data.Maybe (catMaybes)
+import Data.Time
 import Data.Tree
 import Data.Char
 
@@ -41,16 +39,12 @@
 
 data Mix = Mix
              FilePath           -- location of original file
-             Integer            -- time (in seconds) of original file's last update, since 1970.
+             UTCTime            -- time of original file's last update
              Hash               -- hash of mix entry + timestamp
              Int                -- tab stop value.
              [MixEntry]         -- entries
         deriving (Show,Read)
 
--- We would rather use ClockTime in Mix, but ClockTime has no Read instance in 6.4 and before,
--- but does in 6.6. Definining the instance for ClockTime here is the Wrong Thing to do,
--- because if some other program also defined that instance, we will not be able to compile.
-
 type MixEntry = (HpcPos, BoxLabel)
 
 data BoxLabel = ExpBox  Bool -- isAlt
@@ -110,13 +104,6 @@
 
 mixName :: FilePath -> String -> String
 mixName dirName name = dirName ++ "/" ++ name ++ ".mix"
-
--- | Get modification time of a file.
-
-getModificationTime :: FilePath -> IO Integer
-getModificationTime file = do
-  (TOD sec _) <- System.Directory.getModificationTime file
-  return $ sec
 
 ------------------------------------------------------------------------------
 
diff --git a/Trace/Hpc/Util.hs b/Trace/Hpc/Util.hs
--- a/Trace/Hpc/Util.hs
+++ b/Trace/Hpc/Util.hs
@@ -101,7 +101,7 @@
   toHash xs = foldl' (\ h c -> toHash c `hxor` (h * 33)) 5381 xs
 
 instance (HpcHash a,HpcHash b) => HpcHash (a,b) where
-  toHash (a,b) = toHash a * 33 `hxor` toHash b
+  toHash (a,b) = (toHash a * 33) `hxor` toHash b
 
 instance HpcHash HpcPos where
   toHash (P a b c d) = Hash $ fromIntegral $ a * 0x1000000 + b * 0x10000 + c * 0x100 + d
diff --git a/hpc.cabal b/hpc.cabal
--- a/hpc.cabal
+++ b/hpc.cabal
@@ -1,5 +1,5 @@
 name:         hpc
-version:      0.5.1.1
+version:      0.6.0.0
 license:      BSD3
 license-file: LICENSE
 author:       Andy Gill
@@ -26,9 +26,9 @@
     extensions: CPP
     if flag(small_base)
         Build-Depends: base       >= 3   && < 5,
-                       directory  >= 1   && < 1.2,
-                       old-time   >= 1   && < 1.2,
-                       containers >= 0.1 && < 0.5
+                       directory  >= 1   && < 1.3,
+                       time                 < 1.5,
+                       containers >= 0.1 && < 0.6
     else
         Build-Depends: base < 3
     ghc-options: -Wall