diff --git a/Network/Gitit.hs b/Network/Gitit.hs
--- a/Network/Gitit.hs
+++ b/Network/Gitit.hs
@@ -100,6 +100,7 @@
                      , module Network.Gitit.Framework
                      , module Network.Gitit.Layout
                      , module Network.Gitit.ContentTransformer
+                     , module Network.Gitit.Page
                      , getFileStore
                      , getUser
                      , getConfig
@@ -117,6 +118,7 @@
 import Network.Gitit.State
         (getFileStore, getUser, getConfig, queryGititState, updateGititState)
 import Network.Gitit.ContentTransformer
+import Network.Gitit.Page
 import Network.Gitit.Authentication (loginUserForm)
 import Paths_gitit (getDataFileName)
 import Control.Monad.Reader
@@ -147,14 +149,14 @@
 fileServeStrict' :: [FilePath] -> FilePath -> ServerPart Response
 fileServeStrict' ps p = do
   rq <- askRq
-  resp <- fileServeStrict ps p
-  if rsCode resp == 404 || lastNote "fileServeStrict'" (rqUri rq) == '/'
+  resp' <- fileServeStrict ps p
+  if rsCode resp' == 404 || lastNote "fileServeStrict'" (rqUri rq) == '/'
      then mzero  -- pass through if not found or directory index
      else do
        -- turn off compresion filter unless it's text
-       case getHeader "Content-Type" resp of
-            Just ct | B.pack "text/" `B.isPrefixOf` ct -> return resp
-            _ -> ignoreFilters >> return resp
+       case getHeader "Content-Type" resp' of
+            Just ct | B.pack "text/" `B.isPrefixOf` ct -> return resp'
+            _ -> ignoreFilters >> return resp'
 
 wikiHandlers :: [Handler]
 wikiHandlers =
diff --git a/Network/Gitit/ContentTransformer.hs b/Network/Gitit/ContentTransformer.hs
--- a/Network/Gitit/ContentTransformer.hs
+++ b/Network/Gitit/ContentTransformer.hs
@@ -92,7 +92,7 @@
 import qualified Data.ByteString.Lazy as L (toChunks, fromChunks)
 import Network.URL (encString)
 import Network.URI (isUnescapedInURI)
-
+import Text.HTML.SanitizeXSS (sanitizeBalance)
 --
 -- ContentTransformer runners
 --
@@ -225,14 +225,14 @@
 -- | Caches a response (actually just the response body) on disk,
 -- unless the context indicates that the page is not cacheable. 
 cacheHtml :: Response -> ContentTransformer Response 
-cacheHtml resp = do
+cacheHtml resp' = do
   params <- getParams
   file <- getFileName
   cacheable <- getCacheable
   cfg <- lift getConfig
   when (useCache cfg && cacheable && isNothing (pRevision params) && not (pPrintable params)) $
-    lift $ cacheContents file $ S.concat $ L.toChunks $ rsBody resp 
-  return resp 
+    lift $ cacheContents file $ S.concat $ L.toChunks $ rsBody resp'
+  return resp'
 
 -- | Returns cached page if available, otherwise mzero.
 cachedHtml :: ContentTransformer Response
@@ -337,7 +337,8 @@
   toc <- liftM ctxTOC get
   bird <- liftM ctxBirdTracks get
   cfg <- lift getConfig
-  return $ writeHtml defaultWriterOptions{
+  return $ primHtml $ sanitizeBalance $
+           writeHtmlString defaultWriterOptions{
                         writerStandalone = True
                       , writerTemplate = "$if(toc)$\n$toc$\n$endif$\n$body$"
                       , writerHTMLMathMethod =
@@ -489,8 +490,7 @@
 
 readerFor :: PageType -> Bool -> (String -> Pandoc)
 readerFor pt lhs =
-  let defPS = defaultParserState{ stateSanitizeHTML = True
-                                , stateSmart = True
+  let defPS = defaultParserState{ stateSmart = True
                                 , stateLiterateHaskell = lhs }
   in case pt of
        RST      -> readRST defPS
diff --git a/Network/Gitit/Feed.hs b/Network/Gitit/Feed.hs
--- a/Network/Gitit/Feed.hs
+++ b/Network/Gitit/Feed.hs
@@ -21,7 +21,8 @@
 
 module Network.Gitit.Feed (FeedConfig(..), filestoreToXmlFeed) where
 
-import Data.DateTime (addMinutes, formatDateTime, getCurrentTime)
+import Data.Time (UTCTime, formatTime, getCurrentTime, addUTCTime)
+import System.Locale (defaultTimeLocale)
 import Data.Foldable as F (concatMap)
 import Data.List (intercalate, sortBy, nub)
 import Data.Maybe (fromMaybe)
@@ -29,7 +30,7 @@
 import Network.URI (isUnescapedInURI, escapeURIString)
 import System.FilePath (dropExtension, takeExtension, (<.>))
 import Data.FileStore.Types (history, Author(authorName), Change(..),
-         DateTime, FileStore, Revision(..), TimeRange(..))
+         FileStore, Revision(..), TimeRange(..))
 import Text.Atom.Feed (nullEntry, nullFeed, nullLink, nullPerson,
          Date, Entry(..), Feed(..), Link(linkRel), Generator(..),
          Person(personName), TextContent(TextString))
@@ -42,45 +43,46 @@
     fcTitle    :: String
   , fcBaseUrl  :: String
   , fcFeedDays :: Integer
- } deriving (Show, Read)
+ } deriving (Read, Show)
 
+gititGenerator :: Generator
+gititGenerator = Generator {genURI = Just "http://github.com/jgm/gitit"
+                                   , genVersion = Just (showVersion version)
+                                   , genText = "gitit"}
+
 filestoreToXmlFeed :: FeedConfig -> FileStore -> Maybe FilePath -> IO String
-filestoreToXmlFeed cfg f = fmap xmlFeedToString . generateFeed cfg f
+filestoreToXmlFeed cfg f = fmap xmlFeedToString . generateFeed cfg gititGenerator f
 
 xmlFeedToString :: Feed -> String
 xmlFeedToString = ppTopElement . xmlFeed
 
-generateFeed :: FeedConfig -> FileStore -> Maybe FilePath -> IO Feed
-generateFeed cfg fs mbPath = do
+generateFeed :: FeedConfig -> Generator -> FileStore -> Maybe FilePath -> IO Feed
+generateFeed cfg generator fs mbPath = do
   now <- getCurrentTime
   revs <- changeLog (fcFeedDays cfg) fs mbPath now
   let home = fcBaseUrl cfg ++ "/"
   -- TODO: 'nub . sort' `persons` - but no Eq or Ord instances!
       persons = map authorToPerson $ nub $ sortBy (comparing authorName) $ map revAuthor revs
-      basefeed = generateEmptyfeed (fcTitle cfg) home mbPath persons (formatFeedTime now)
+      basefeed = generateEmptyfeed generator (fcTitle cfg) home mbPath persons (formatFeedTime now)
       revisions = map (revisionToEntry home) revs
   return basefeed {feedEntries = revisions}
 
 -- | Get the last N days history.
-changeLog :: Integer -> FileStore -> Maybe FilePath ->DateTime -> IO [Revision]
+changeLog :: Integer -> FileStore -> Maybe FilePath -> UTCTime -> IO [Revision]
 changeLog days a mbPath now' = do
   let files = F.concatMap (\f -> [f, f <.> "page"]) mbPath
-  let startTime = addMinutes (-60 * 24 * days) now'
+  let startTime = addUTCTime (fromIntegral $ -60 * 60 * 24 * days) now'
   rs <- history a files TimeRange{timeFrom = Just startTime, timeTo = Just now'}
   return $ sortBy (comparing revDateTime) rs
 
-generateEmptyfeed :: String ->String ->Maybe String -> [Person] -> Date -> Feed
-generateEmptyfeed title home mbPath authors now =
+generateEmptyfeed :: Generator -> String ->String ->Maybe String -> [Person] -> Date -> Feed
+generateEmptyfeed generator title home mbPath authors now =
   baseNull {feedAuthors = authors,
-            feedGenerator = Just gititGenerator,
+            feedGenerator = Just generator,
             feedLinks = [ (nullLink $ home ++ "_feed/" ++ escape (fromMaybe "" mbPath))
                            {linkRel = Just (Left "self")}]
             }
     where baseNull = nullFeed home (TextString title) now
-          gititGenerator :: Generator
-          gititGenerator = Generator {genURI = Just "http://github.com/jgm/gitit"
-                                     , genVersion = Just (showVersion version)
-                                     , genText = "gitit"}
 
 revisionToEntry :: String -> Revision -> Entry
 revisionToEntry home Revision{ revId = rid, revDateTime = rdt,
@@ -101,8 +103,8 @@
 escape :: String -> String
 escape = escapeURIString isUnescapedInURI
 
-formatFeedTime :: DateTime -> String
-formatFeedTime = formatDateTime "%FT%TZ"
+formatFeedTime :: UTCTime -> String
+formatFeedTime = formatTime defaultTimeLocale "%FT%TZ"
 
 -- TODO: this boilerplate can be removed by changing Data.FileStore.Types to say
 -- data Change = Modified {extract :: FilePath} | Deleted {extract :: FilePath} | Added
diff --git a/Network/Gitit/Handlers.hs b/Network/Gitit/Handlers.hs
--- a/Network/Gitit/Handlers.hs
+++ b/Network/Gitit/Handlers.hs
@@ -81,7 +81,7 @@
 import qualified Data.ByteString.Lazy as B
 import qualified Data.ByteString as S
 import Network.HTTP (urlEncodeVars)
-import Data.DateTime (getCurrentTime, addMinutes)
+import Data.Time (getCurrentTime, addUTCTime)
 import Data.FileStore
 import System.Log.Logger (logM, Priority(..))
 
@@ -326,7 +326,7 @@
 showHistory :: String -> String -> Params -> Handler
 showHistory file page params =  do
   currTime <- liftIO getCurrentTime
-  let oneYearAgo = addMinutes (-1 * 60 * 24 * 365) currTime
+  let oneYearAgo = addUTCTime (-60 * 60 * 24 * 365) currTime
   let since = case pSince params of
                    Nothing -> Just oneYearAgo
                    Just t  -> Just t
@@ -379,7 +379,7 @@
 showActivity :: Handler
 showActivity = withData $ \(params :: Params) -> do
   currTime <- liftIO getCurrentTime
-  let oneMonthAgo = addMinutes (-1 * 60 * 24 * 30) currTime
+  let oneMonthAgo = addUTCTime (-60 * 60 * 24 * 30) currTime
   let since = case pSince params of
                    Nothing -> Just oneMonthAgo
                    Just t  -> Just t
@@ -776,6 +776,6 @@
             ok $ emptyResponse{rsBody = B.fromChunks [contents]}
        _ -> do
             fs <- getFileStore
-            resp <- liftM toResponse $ liftIO (filestoreToXmlFeed fc fs mbPath)
-            cacheContents file $ S.concat $ B.toChunks $ rsBody resp
-            ok . setContentType "application/atom+xml; charset=UTF-8" $ resp
+            resp' <- liftM toResponse $ liftIO (filestoreToXmlFeed fc fs mbPath)
+            cacheContents file $ S.concat $ B.toChunks $ rsBody resp'
+            ok . setContentType "application/atom+xml; charset=UTF-8" $ resp'
diff --git a/Network/Gitit/Initialize.hs b/Network/Gitit/Initialize.hs
--- a/Network/Gitit/Initialize.hs
+++ b/Network/Gitit/Initialize.hs
@@ -118,8 +118,7 @@
     let fs = filestoreFromConfig conf
         pt = defaultPageType conf
         toPandoc = readMarkdown
-                   defaultParserState{ stateSanitizeHTML = True
-                                     , stateSmart = True }
+                   defaultParserState{ stateSmart = True }
         defOpts = defaultWriterOptions{
                           writerStandalone = False
                         , writerHTMLMathMethod = JsMath
diff --git a/Network/Gitit/Plugins.hs b/Network/Gitit/Plugins.hs
--- a/Network/Gitit/Plugins.hs
+++ b/Network/Gitit/Plugins.hs
@@ -56,7 +56,12 @@
       pr <- findModule (mkModuleName "Prelude") Nothing
       i <- findModule (mkModuleName "Network.Gitit.Interface") Nothing
       m <- findModule (mkModuleName modName) Nothing
-      setContext [] [m, i, pr]
+      setContext []
+#if MIN_VERSION_ghc(7,0,0)
+        [(m, Nothing), (i, Nothing), (pr, Nothing)]
+#else
+        [m, i, pr]
+#endif
       value <- compileExpr (modName ++ ".plugin :: Plugin")
       let value' = (unsafeCoerce value) :: Plugin
       return value'
diff --git a/Network/Gitit/State.hs b/Network/Gitit/State.hs
--- a/Network/Gitit/State.hs
+++ b/Network/Gitit/State.hs
@@ -25,7 +25,6 @@
 import System.Random (randomRIO)
 import Data.Digest.Pure.SHA (sha512, showDigest)
 import qualified Data.ByteString.Lazy.UTF8 as L (fromString)
-import qualified System.IO.Cautious as C (writeFile)
 import Data.IORef
 import System.IO.Unsafe (unsafePerformIO)
 import Control.Monad.Reader
@@ -101,7 +100,7 @@
 writeUserFile :: Config -> IO ()
 writeUserFile conf = do
   usrs <- queryGititState users
-  C.writeFile (userFile conf) $
+  writeFile (userFile conf) $
       "[" ++ intercalate "\n," (map show $ M.toList usrs) ++ "\n]"
 
 getUser :: String -> GititServerPart (Maybe User)
diff --git a/Network/Gitit/Types.hs b/Network/Gitit/Types.hs
--- a/Network/Gitit/Types.hs
+++ b/Network/Gitit/Types.hs
@@ -33,7 +33,8 @@
 import qualified Data.ByteString.Lazy as L (empty)
 import qualified Data.Map as M
 import Data.List (intersect)
-import Data.DateTime
+import Data.Time (parseTime)
+import System.Locale (defaultTimeLocale)
 import Data.Maybe (fromMaybe)
 import Data.FileStore.Types
 import Network.Gitit.Server
@@ -252,7 +253,7 @@
                      , pRevision     :: Maybe String
                      , pDestination  :: String
                      , pForUser      :: Maybe String
-                     , pSince        :: Maybe DateTime
+                     , pSince        :: Maybe UTCTime
                      , pRaw          :: String
                      , pLimit        :: Int
                      , pPatterns     :: [String]
@@ -289,7 +290,7 @@
                  return (if null s then Nothing else Just s))
                  `mplus` return Nothing
          fu <- liftM Just (look' "forUser") `mplus` return Nothing
-         si <- liftM (parseDateTime "%Y-%m-%d") (look' "since")
+         si <- liftM (parseTime defaultTimeLocale "%Y-%m-%d") (look' "since")
                  `mplus` return Nothing  -- YYYY-mm-dd format
          ds <- look' "destination" `mplus` return ""
          ra <- look' "raw"            `mplus` return ""
diff --git a/README.markdown b/README.markdown
--- a/README.markdown
+++ b/README.markdown
@@ -297,7 +297,7 @@
 To change the footer, modify `templates/footer.st`.
 
 For more radical changes, you can override any of the default
-templates in `$CABALDIR/share/gitit-x.y.z/templates` by copying
+templates in `$CABALDIR/share/gitit-x.y.z/data/templates` by copying
 the file into `templates` and modifying it. The `page.st` template is
 the master template; it includes the others. Interpolated variables are
 surrounded by `$`s, so `literal $` must be backslash-escaped.
diff --git a/data/static/js/preview.js b/data/static/js/preview.js
--- a/data/static/js/preview.js
+++ b/data/static/js/preview.js
@@ -1,8 +1,15 @@
 function updatePreviewPane() {
     $("#previewpane").hide();
     var url = location.pathname.replace(/_edit\//,"_preview/");
-    $("#previewpane").load(url, { "raw" : $("#editedText").attr("value") }, function() {convert();} );
-    $("#previewpane").fadeIn(1000);
+    $.post(
+      url,
+      {"raw" : $("#editedText").attr("value")},
+      function(data) {
+        $('#previewpane').html(data);
+        if (typeof(convert) == 'function') { convert(); }
+      },
+      "html");
+    $('#previewpane').fadeIn(1000);
 };
 $(document).ready(function(){
     $("#previewButton").show();
diff --git a/data/templates/logo.st b/data/templates/logo.st
--- a/data/templates/logo.st
+++ b/data/templates/logo.st
@@ -1,3 +1,3 @@
 <div id="logo">
-  <a href="$base$/" title="Go to top page"><img src="$base$/img/logo.png" /></a>
+  <a href="$base$/" alt="site logo" title="Go to top page"><img src="$base$/img/logo.png" /></a>
 </div>
diff --git a/gitit.cabal b/gitit.cabal
--- a/gitit.cabal
+++ b/gitit.cabal
@@ -1,5 +1,5 @@
 name:                gitit
-version:             0.7.3.8
+version:             0.7.3.9
 Cabal-version:       >= 1.2
 build-type:          Simple
 synopsis:            Wiki using happstack, git or darcs, and pandoc.
@@ -100,7 +100,7 @@
     exposed-modules: Network.Gitit.Interface
     build-depends:   ghc, ghc-paths
     cpp-options:     -D_PLUGINS
-  build-depends:     base >= 3, pandoc >= 1.6, filepath, safe
+  build-depends:     base >= 3, pandoc >= 1.6 && < 1.7, filepath, safe
   extensions:        CPP
   if impl(ghc >= 6.12)
     ghc-options:     -Wall -fno-warn-unused-do-bind
@@ -111,21 +111,39 @@
 Executable           gitit
   hs-source-dirs:    .
   main-is:           gitit.hs
-  build-depends:     base >=3 && < 5, parsec, pretty, xhtml, containers,
-                     pandoc >= 1.6, process, filepath, directory, mtl, cgi,
-                     network, old-time, highlighting-kate >= 0.2.7.1, bytestring,
+  build-depends:     base >=3 && < 5,
+                     parsec,
+                     pretty,
+                     xhtml,
+                     containers,
+                     pandoc >= 1.6 && < 1.7,
+                     process,
+                     filepath,
+                     directory,
+                     mtl,
+                     cgi,
+                     network,
+                     old-time,
+                     highlighting-kate >= 0.2.7.1,
+                     bytestring,
+                     random,
                      utf8-string >= 0.3 && < 0.4,
-                     SHA > 1 && < 1.5, HTTP >= 4000.0 && < 4000.1,
-                     HStringTemplate >= 0.6 && < 0.7, random,
-                     network >= 2.1.0.0 && < 2.3,
-                     recaptcha >= 0.1, filestore >= 0.3.4,
-                     datetime >= 0.1 && < 0.3, zlib >= 0.5 && < 0.6,
+                     SHA > 1 && < 1.5, HTTP >= 4000.0 && < 4000.2,
+                     HStringTemplate >= 0.6 && < 0.7,
+                     network >= 2.1.0.0 && < 2.4,
+                     old-locale >= 1,
+                     time >= 1.1 && < 1.2,
+                     recaptcha >= 0.1,
+                     filestore >= 0.4 && < 0.5,
+                     zlib >= 0.5 && < 0.6,
                      url >= 2.1 && < 2.2,
                      happstack-server >= 0.5 && < 0.6,
-                     happstack-util >= 0.5 && < 0.6, xml >= 1.3.5,
-                     hslogger >= 1 && < 1.1, ConfigFile >= 1 && < 1.1,
+                     happstack-util >= 0.5 && < 0.6,
+                     xml >= 1.3.5,
+                     hslogger >= 1 && < 1.2,
+                     ConfigFile >= 1 && < 1.1,
                      feed >= 0.3.6 && < 0.4,
-                     cautious-file >= 0.1.5 && < 0.2
+                     xss-sanitize >= 0.2 && < 0.3
   if impl(ghc >= 6.10)
     build-depends:   base >= 4, syb
   if flag(plugins)
diff --git a/plugins/Subst.hs b/plugins/Subst.hs
--- a/plugins/Subst.hs
+++ b/plugins/Subst.hs
@@ -6,7 +6,8 @@
 
 module Subst (plugin) where
 
-import Data.FileStore (retrieve)
+import Control.Monad.CatchIO (try)
+import Data.FileStore (FileStoreError, retrieve)
 import Text.Pandoc (defaultParserState, readMarkdown)
 import Network.Gitit.ContentTransformer (inlinesToString)
 import Network.Gitit.Interface
@@ -16,12 +17,17 @@
 plugin = mkPageTransformM substituteIntoBlock
 
 substituteIntoBlock :: [Block] -> PluginM [Block]
-substituteIntoBlock (Para (Link ref ("!subst", _):_ ):xs) = 
-     do let target = inlinesToString ref ++ ".page"
+substituteIntoBlock ((Para [Link ref ("!subst", _)]):xs) = 
+     do let target = inlinesToString ref 
         cfg <- askConfig
         let fs = filestoreFromConfig cfg
-        article <- liftIO (retrieve fs target Nothing)
-        let (Pandoc _ content) = readMarkdown defaultParserState article
-        (content ++) `fmap` substituteIntoBlock xs
+        article <- try $ liftIO (retrieve fs (target ++ ".page") Nothing) 
+        case article :: Either FileStoreError String of
+          Left  _    -> let txt = Str ("[" ++ target ++ "](!subst)")
+                            alt = "'" ++ target ++ "' doesn't exist. Click here to create it."
+                            lnk = Para [Link [txt] (target,alt)]
+                        in  (lnk :) `fmap` substituteIntoBlock xs
+          Right a    -> let (Pandoc _ content) = readMarkdown defaultParserState a
+                        in  (content ++) `fmap` substituteIntoBlock xs
 substituteIntoBlock (x:xs) = (x:) `fmap` substituteIntoBlock xs
 substituteIntoBlock [] = return []