diff --git a/gitrev.cabal b/gitrev.cabal
--- a/gitrev.cabal
+++ b/gitrev.cabal
@@ -1,5 +1,5 @@
 name:                gitrev
-version:             1.1.0
+version:             1.2.0
 synopsis:            Compile git revision info into Haskell projects
 homepage:            https://github.com/acfoltzer/gitrev
 license:             BSD3
@@ -16,7 +16,7 @@
   location: https://github.com/acfoltzer/gitrev.git
 
 library
-  build-depends:       base >= 4.7 && < 5,
+  build-depends:       base >= 4.6 && < 5,
                        directory,
                        filepath,
                        template-haskell,
diff --git a/src/Development/GitRev.hs b/src/Development/GitRev.hs
--- a/src/Development/GitRev.hs
+++ b/src/Development/GitRev.hs
@@ -18,6 +18,7 @@
 -- > panic msg = error panicMsg
 -- >   where panicMsg =
 -- >           concat [ "[panic ", $(gitBranch), "@", $(gitHash)
+-- >                  , " (", $(gitCommitDate), ")"
 -- >                  , " (", $(gitCommitCount), " commits in HEAD)"
 -- >                  , dirty, "] ", msg ]
 -- >         dirty | $(gitDirty) = " (uncommitted files present)"
@@ -26,9 +27,9 @@
 -- > main = panic "oh no!"
 --
 -- > % cabal exec runhaskell Example.hs
--- > Example.hs: [panic master@2702e69355c978805064543489c351b61ac6760b (6 commits in HEAD) (uncommitted files present)] oh no!
+-- > Example.hs: [panic master@2ae047ba5e4a6f0f3e705a43615363ac006099c1 (Mon Jan 11 11:50:59 2016 -0800) (14 commits in HEAD) (uncommitted files present)] oh no!
 
-module Development.GitRev (gitHash, gitBranch, gitDirty, gitCommitCount) where
+module Development.GitRev (gitHash, gitBranch, gitDirty, gitCommitCount, gitCommitDate) where
 
 import Control.Applicative
 import Control.Exception
@@ -44,8 +45,8 @@
 -- | Run git with the given arguments and no stdin, returning the
 -- stdout output. If git isn't available or something goes wrong,
 -- return the second argument.
-runGit :: [String] -> String -> Q String
-runGit args def = do
+runGit :: [String] -> String -> IndexUsed -> Q String
+runGit args def useIdx = do
   let oops :: SomeException -> IO (ExitCode, String, String)
       oops _e = return (ExitFailure 1, def, "")
   gitFound <- runIO $ isJust <$> findExecutable "git"
@@ -71,7 +72,7 @@
           _hash -> addDependentFile hd
       -- add the index if it exists to set the dirty flag
       indexExists <- runIO $ doesFileExist index
-      when indexExists $ addDependentFile index
+      when (indexExists && useIdx == IdxUsed) $ addDependentFile index
       -- if the refs have been packed, the info we're looking for
       -- might be in that file rather than the one-file-per-ref case
       -- handled above
@@ -84,29 +85,39 @@
           ExitFailure _ -> return def
     else return def
 
+-- | Type to flag if the git index is used or not in a call to runGit
+data IndexUsed = IdxUsed -- ^ The git index is used
+               | IdxNotUsed -- ^ The git index is /not/ used
+    deriving (Eq)
+
 -- | Return the hash of the current git commit, or @UNKNOWN@ if not in
 -- a git repository
 gitHash :: ExpQ
 gitHash =
-  stringE =<< runGit ["rev-parse", "HEAD"] "UNKNOWN"
+  stringE =<< runGit ["rev-parse", "HEAD"] "UNKNOWN" IdxNotUsed
 
 -- | Return the branch (or tag) name of the current git commit, or @UNKNOWN@
 -- if not in a git repository. For detached heads, this will just be
 -- "HEAD"
 gitBranch :: ExpQ
 gitBranch =
-  stringE =<< runGit ["rev-parse", "--abbrev-ref", "HEAD"] "UNKNOWN"
+  stringE =<< runGit ["rev-parse", "--abbrev-ref", "HEAD"] "UNKNOWN" IdxNotUsed
 
 -- | Return @True@ if there are non-committed files present in the
 -- repository
 gitDirty :: ExpQ
 gitDirty = do
-  output <- runGit ["status", "--porcelain"] ""
+  output <- runGit ["status", "--porcelain"] "" IdxUsed
   case output of
-    "" -> conE $ mkName "Prelude.False"
-    _  -> conE $ mkName "Prelude.True"
+    "" -> conE falseName
+    _  -> conE trueName
 
 -- | Return the number of commits in the current head
 gitCommitCount :: ExpQ
 gitCommitCount =
-  stringE =<< runGit ["rev-list", "HEAD", "--count"] "UNKNOWN"
+  stringE =<< runGit ["rev-list", "HEAD", "--count"] "UNKNOWN" IdxNotUsed
+
+-- | Return the commit date of the current head
+gitCommitDate :: ExpQ
+gitCommitDate =
+  stringE =<< runGit ["log", "HEAD", "-1", "--format=%cd"] "UNKNOWN" IdxNotUsed