diff --git a/DAV.cabal b/DAV.cabal
--- a/DAV.cabal
+++ b/DAV.cabal
@@ -1,5 +1,5 @@
 name:                DAV
-version:             1.0.7
+version:             1.1
 synopsis:            RFC 4918 WebDAV support
 description:
    This is a library for the Web Distributed Authoring and Versioning
@@ -34,15 +34,16 @@
                      , case-insensitive >= 0.4
                      , containers
                      , data-default
-                     , either >= 4.3
-                     , exceptions
+                     , exceptions >= 0.7
                      , http-client >= 0.2
                      , http-client-tls >= 0.2
                      , http-types >= 0.7
                      , lens >= 3.0
                      , mtl >= 2.1
+                     , mtl-compat
                      , transformers >= 0.3
                      , transformers-base
+                     , transformers-compat >= 0.3
                      , utf8-string
                      , xml-conduit >= 1.0
                      , xml-hamlet >= 0.4           && < 0.5
@@ -55,16 +56,17 @@
                      , case-insensitive >= 0.4
                      , containers
                      , data-default
-                     , either >= 4.3
-                     , exceptions
+                     , exceptions >= 0.7
                      , http-client >= 0.2
                      , http-client-tls >= 0.2
                      , http-types >= 0.7
                      , lens >= 3.0
                      , mtl >= 2.1
+                     , mtl-compat
                      , optparse-applicative >= 0.10.0
                      , transformers >= 0.3
                      , transformers-base
+                     , transformers-compat >= 0.3
                      , utf8-string
                      , xml-conduit >= 1.0
                      , xml-hamlet >= 0.4           && < 0.5
@@ -81,4 +83,4 @@
 source-repository this
   type:     git
   location: git://anonscm.debian.org/users/clint/DAV.git
-  tag:      DAV/1.0.7
+  tag:      DAV/1.1
diff --git a/Network/Protocol/HTTP/DAV.hs b/Network/Protocol/HTTP/DAV.hs
--- a/Network/Protocol/HTTP/DAV.hs
+++ b/Network/Protocol/HTTP/DAV.hs
@@ -53,16 +53,15 @@
 import Network.Protocol.HTTP.DAV.TH
 
 import Control.Applicative (liftA2, Alternative, Applicative)
-import Control.Monad.Trans.Either (EitherT(..))
+import Control.Monad.Trans.Except (ExceptT(..), throwE)
 import Control.Lens ((^.), (.=), (%=), (.~))
 import Control.Monad (when, MonadPlus)
 import Control.Monad.Base (MonadBase(..))
 import Control.Monad.Catch (bracket, bracketOnError, catchJust, finally, throwM, mask, uninterruptibleMask, MonadCatch, MonadMask, MonadThrow)
 import qualified Control.Monad.Catch as MonadCatch
-import Control.Monad.Error (MonadError)
+import Control.Monad.Except (MonadError)
 import Control.Monad.Fix (MonadFix)
 import Control.Monad.Trans.Class (lift, MonadTrans)
-import Control.Monad.Trans.Either (left)
 import Control.Monad.IO.Class (liftIO, MonadIO)
 import Control.Monad.State (evalStateT, runStateT, get, MonadState, StateT)
 
@@ -88,15 +87,15 @@
 instance Default DAVContext where
     def = DAVContext [] def B.empty B.empty [] Nothing def Nothing "hDav-using application"
 
-newtype DAVT m a = DAVT { runDAVT :: EitherT String (StateT DAVContext m) a }
+newtype DAVT m a = DAVT { runDAVT :: ExceptT String (StateT DAVContext m) a }
     deriving (Alternative, Applicative, Functor, Monad, MonadBase b, MonadError String, MonadFix, MonadIO, MonadPlus, MonadState DAVContext)
 
 -- this orphan instance is probably a bad idea
-instance MonadMask m => MonadMask (EitherT e m) where
-    mask a = EitherT $ mask $ \u -> runEitherT (a $ q u)
-        where q u = EitherT . u . runEitherT
-    uninterruptibleMask a = EitherT $ uninterruptibleMask $ \u -> runEitherT (a $ q u)
-        where q u = EitherT . u . runEitherT
+instance MonadMask m => MonadMask (ExceptT e m) where
+    mask a = ExceptT $ mask $ \u -> runExceptT (a $ q u)
+        where q u = ExceptT . u . runExceptT
+    uninterruptibleMask a = ExceptT $ uninterruptibleMask $ \u -> runExceptT (a $ q u)
+        where q u = ExceptT . u . runExceptT
 
 instance MonadCatch m => MonadCatch (DAVT m) where
     catch (DAVT m) f = DAVT $ MonadCatch.catch m (runDAVT . f)
@@ -118,7 +117,7 @@
 evalDAVT :: MonadIO m => DAVURL -> DAVT m a -> m (Either String a)
 evalDAVT u f = do
     ctx <- mkDAVContext u
-    r <- (evalStateT . runEitherT . runDAVT) f ctx
+    r <- (evalStateT . runExceptT . runDAVT) f ctx
     closeDAVContext ctx
     return r
 
@@ -135,7 +134,7 @@
 withDAVContext u = bracket (mkDAVContext u) closeDAVContext
 
 runDAVContext :: MonadIO m => DAVContext -> DAVT m a -> m (Either String a, DAVContext)
-runDAVContext ctx f = (runStateT . runEitherT . runDAVT) f ctx
+runDAVContext ctx f = (runStateT . runExceptT . runDAVT) f ctx
 
 setCreds :: MonadIO m => B.ByteString -> B.ByteString -> DAVT m ()
 setCreds u p = basicusername .= u >> basicpassword .= p
@@ -167,7 +166,7 @@
   where
     go req = do
       ctx <- get
-      maybe (DAVT $ left "Can't perform request without manager") (liftIO . httpLbs req) (ctx ^. httpManager)
+      maybe (DAVT $ throwE "Can't perform request without manager") (liftIO . httpLbs req) (ctx ^. httpManager)
 
 matchStatusCodeException :: Status -> HttpException -> Maybe ()
 matchStatusCodeException want (StatusCodeException s _ _)
@@ -202,16 +201,13 @@
     d <- get
     case _lockToken d of
         Nothing -> return ()
-	Just tok -> do let ahs = [(mk "Lock-Token", tok)]
+        Just tok -> do let ahs = [(mk "Lock-Token", tok)]
                        _ <- davRequest "UNLOCK" ahs emptyBody
                        lockToken .= Nothing
 
 supportsLocking :: DAVContext -> Bool
 supportsLocking = liftA2 (&&) ("LOCK" `elem`) ("UNLOCK" `elem`) . _allowedMethods
 
-supportsCalDAV :: DAVContext -> Bool
-supportsCalDAV = ("calendar-access" `elem`) . _complianceClasses
-
 getPropsM :: MonadIO m => DAVT m XML.Document
 getPropsM = do
     let ahs = [(hContentType, "application/xml; charset=\"utf-8\"")]
@@ -230,7 +226,7 @@
 withContentM handleresponse = do
     req <- mkDavRequest "GET" [] emptyBody
     ctx <- get
-    maybe (DAVT $ left "Can't handle response without manager") (\mgr -> liftIO $ withResponse req mgr handleresponse) (ctx ^. httpManager)
+    maybe (DAVT $ throwE "Can't handle response without manager") (\mgr -> liftIO $ withResponse req mgr handleresponse) (ctx ^. httpManager)
 
 -- | Note that the entire request body is buffered in memory; not suitable
 -- for large files.
@@ -288,8 +284,8 @@
        root [] = propertyupdate []
        root prop = propertyupdate
            [ XML.NodeElement $ XML.Element "D:set" Map.empty
-	     [ XML.NodeElement $ XML.Element "D:prop" Map.empty prop ]
-	   ]
+             [ XML.NodeElement $ XML.Element "D:prop" Map.empty prop ]
+           ]
        propertyupdate = XML.Element "D:propertyupdate" (Map.fromList [("xmlns:D", "DAV:")])
        blacklist = [ "{DAV:}creationdate"
                    , "{DAV:}displayname"
@@ -382,7 +378,7 @@
     let r = ctx ^. baseRequest
         r' = r { path = adjustpath r }
         ctx' = baseRequest .~ r' $ ctx
-    lift $ either error return =<< (evalStateT . runEitherT . runDAVT) a ctx'
+    lift $ either error return =<< (evalStateT . runExceptT . runDAVT) a ctx'
   where
     adjustpath = UTF8B.fromString . f . UTF8B.toString . path