diff --git a/.gitignore b/.gitignore
--- a/.gitignore
+++ b/.gitignore
@@ -11,3 +11,5 @@
 *.hi
 *~
 *#
+.cabal-sandbox/
+cabal.sandbox.config
diff --git a/.travis.yml b/.travis.yml
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,104 @@
-language: haskell
+# This file has been generated -- see https://github.com/hvr/multi-ghc-travis
+language: c
+sudo: false
+
+cache:
+  directories:
+    - $HOME/.cabsnap
+    - $HOME/.cabal/packages
+
+before_cache:
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/build-reports.log
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/00-index.tar
+
+matrix:
+  include:
+    - env: CABALVER=1.18 GHCVER=7.4.2
+      compiler: ": #GHC 7.4.2"
+      addons: {apt: {packages: [cabal-install-1.18,ghc-7.4.2], sources: [hvr-ghc]}}
+    - env: CABALVER=1.18 GHCVER=7.6.3
+      compiler: ": #GHC 7.6.3"
+      addons: {apt: {packages: [cabal-install-1.18,ghc-7.6.3], sources: [hvr-ghc]}}
+    - env: CABALVER=1.18 GHCVER=7.8.4
+      compiler: ": #GHC 7.8.4"
+      addons: {apt: {packages: [cabal-install-1.18,ghc-7.8.4], sources: [hvr-ghc]}}
+    - env: CABALVER=1.22 GHCVER=7.10.3
+      compiler: ": #GHC 7.10.3"
+      addons: {apt: {packages: [cabal-install-1.22,ghc-7.10.3], sources: [hvr-ghc]}}
+    - env: CABALVER=1.24 GHCVER=8.0.2
+      compiler: ": #GHC 8.0.2"
+      addons: {apt: {packages: [cabal-install-1.24,ghc-8.0.2], sources: [hvr-ghc]}}
+    - env: CABALVER=2.0 GHCVER=8.2.1
+      compiler: ": #GHC 8.2.1"
+      addons: {apt: {packages: [cabal-install-2.0,ghc-8.2.1], sources: [hvr-ghc]}}
+    - env: CABALVER=head GHCVER=head
+      compiler: ": #GHC head"
+      addons: {apt: {packages: [cabal-install-head,ghc-head], sources: [hvr-ghc]}}
+
+  allow_failures:
+    - env: CABALVER=head GHCVER=head
+
+before_install:
+ - unset CC
+ - export PATH=$HOME/.cabal/bin:/opt/ghc/$GHCVER/bin:/opt/cabal/$CABALVER/bin:$PATH
+
+install:
+ - cabal --version
+ - echo "$(ghc --version) [$(ghc --print-project-git-commit-id 2> /dev/null || echo '?')]"
+ - if [ -f $HOME/.cabal/packages/hackage.haskell.org/00-index.tar.gz ];
+   then
+     zcat $HOME/.cabal/packages/hackage.haskell.org/00-index.tar.gz >
+          $HOME/.cabal/packages/hackage.haskell.org/00-index.tar;
+   fi
+ - travis_retry cabal update -v
+ - sed -i 's/^jobs:/-- jobs:/' ${HOME}/.cabal/config
+ - cabal install --only-dependencies --dry -v > installplan.txt
+ - sed -i -e '1,/^Resolving /d' installplan.txt; cat installplan.txt
+
+# check whether current requested install-plan matches cached package-db snapshot
+ - if diff -u installplan.txt $HOME/.cabsnap/installplan.txt;
+   then
+     echo "cabal build-cache HIT";
+     rm -rfv .ghc;
+     cp -a $HOME/.cabsnap/ghc $HOME/.ghc;
+     cp -a $HOME/.cabsnap/lib $HOME/.cabsnap/share $HOME/.cabsnap/bin $HOME/.cabal/;
+   else
+     echo "cabal build-cache MISS";
+     rm -rf $HOME/.cabsnap;
+     mkdir -p $HOME/.ghc $HOME/.cabal/lib $HOME/.cabal/share $HOME/.cabal/bin;
+     cabal install -j --only-dependencies;
+   fi
+
+# snapshot package-db on cache miss
+ - if [ ! -d $HOME/.cabsnap ];
+   then
+      echo "snapshotting package-db to build-cache";
+      mkdir $HOME/.cabsnap;
+      cp -a $HOME/.ghc $HOME/.cabsnap/ghc;
+      cp -a $HOME/.cabal/lib $HOME/.cabal/share $HOME/.cabal/bin installplan.txt $HOME/.cabsnap/;
+   fi
+
+# Here starts the actual work to be performed for the package under test;
+# any command which exits with a non-zero exit code causes the build to fail.
+script:
+ - cabal configure -v2 # -v2 provides useful information for debugging
+ - cabal build # this builds all libraries and executables (including tests/benchmarks)
+ - cabal sdist   # tests that a source-distribution can be generated
+ - export SRC_TGZ=$(cabal info . | awk '{print $2 ".tar.gz";exit}') ;
+   cd dist/;
+   if [ -f "$SRC_TGZ" ]; then
+      cabal install "$SRC_TGZ";
+   else
+      echo "expected '$SRC_TGZ' not found";
+      exit 1;
+   fi
+
 notifications:
   irc:
     channels:
       - "irc.freenode.org#haskell-lens"
     skip_join: true
     template:
-      - "\x0313either\x03/\x0306%{branch}\x03 \x0314%{commit}\x03 %{build_url} %{message}"
+      - "\x0313either\x0f/\x0306%{branch}\x0f \x0314%{commit}\x0f %{message} \x0302\x1f%{build_url}\x0f"
+
+# EOF
diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,9 @@
+4.5
+----
+* Add `MMonad` instance for `EitherT`
+* Deprecate `Control.Monad.Trans.Either` in favor of `Control.Monad.Trans.Except`
+* Add `firstEitherT`
+
 4.4.1.1
 -------
 * Fixed building on newer GHCs. (type synonyms require explicit foralls for unused variables these days)
diff --git a/either.cabal b/either.cabal
--- a/either.cabal
+++ b/either.cabal
@@ -1,6 +1,6 @@
 name:          either
 category:      Control, Monads
-version:       4.4.1.1
+version:       4.5
 license:       BSD3
 cabal-version: >= 1.6
 license-file:  LICENSE
@@ -32,9 +32,9 @@
     exceptions        >= 0.5     && < 0.9,
     free              >= 4.9     && < 5,
     monad-control     >= 0.3.2   && < 1.1,
-    MonadRandom       >= 0.1     && < 0.5,
+    MonadRandom       >= 0.1     && < 0.6,
     mtl               >= 2.0     && < 2.3,
-    mmorph            >= 1.0.0   && < 1.1,
+    mmorph            >= 1.0.0   && < 1.2,
     profunctors       >= 4       && < 6,
     semigroups        >= 0.8.3.1 && < 1,
     semigroupoids     >= 4       && < 6,
diff --git a/src/Control/Monad/Trans/Either.hs b/src/Control/Monad/Trans/Either.hs
--- a/src/Control/Monad/Trans/Either.hs
+++ b/src/Control/Monad/Trans/Either.hs
@@ -1,8 +1,4 @@
 {-# LANGUAGE CPP #-}
-#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 702
-{-# LANGUAGE Trustworthy #-}
-#endif
-
 {-# LANGUAGE FlexibleInstances     #-}
 {-# LANGUAGE FlexibleContexts      #-}
 {-# LANGUAGE UndecidableInstances  #-}
@@ -23,6 +19,7 @@
 -----------------------------------------------------------------------------
 
 module Control.Monad.Trans.Either
+{-# DEPRECATED "Use \"Control.Monad.Trans.Except\" from transformers or transformers-compat instead." #-}
   ( EitherT(..)
   , eitherT
   , bimapEitherT
@@ -33,6 +30,7 @@
   , left
   , right
   , swapEitherT
+  , firstEitherT
   ) where
 
 import Control.Applicative
@@ -50,13 +48,17 @@
 import Control.Monad.Trans.Control (MonadBaseControl(..), MonadTransControl(..), defaultLiftBaseWith, defaultRestoreM)
 import Control.Monad.Writer.Class
 import Control.Monad.Random (MonadRandom,getRandom,getRandoms,getRandomR,getRandomRs)
-import Control.Monad.Morph (MFunctor, hoist)
+import Control.Monad.Morph (MFunctor(..), MMonad(..))
 import Data.Either.Combinators ( swapEither )
+#if __GLASGOW_HASKELL__ < 710
 import Data.Foldable
+#endif
 import Data.Function (on)
 import Data.Functor.Bind
 import Data.Functor.Plus
+#if __GLASGOW_HASKELL__ < 710
 import Data.Traversable
+#endif
 import Data.Semigroup
 
 -- | 'EitherT' is a version of 'Control.Monad.Trans.Error.ErrorT' that does not
@@ -98,6 +100,15 @@
   hoist f = EitherT . f . runEitherT
   {-# INLINE hoist #-}
 
+instance MMonad (EitherT e) where
+  embed f m = EitherT $ do
+    x <- runEitherT . f . runEitherT $ m
+    return $ case x of
+        Left         e  -> Left e
+        Right (Left  e) -> Left e
+        Right (Right a) -> Right a
+  {-# INLINE embed #-}
+
 -- | Given a pair of actions, one to perform in case of failure, and one to perform
 -- in case of success, run an 'EitherT' and get back a monadic result.
 eitherT :: Monad m => (a -> m c) -> (b -> m c) -> EitherT a m b -> m c
@@ -122,6 +133,11 @@
   h (Left e)  = Left (f e)
   h (Right a) = Right (g a)
 {-# INLINE bimapEitherT #-}
+
+-- | Map over failure
+firstEitherT :: Functor m => (e -> f) -> EitherT e m a -> EitherT f m a
+firstEitherT f = bimapEitherT f id
+{-# INLINE firstEitherT #-}
 
 -- | Map the unwrapped computation using the given function.
 --
diff --git a/src/Data/Either/Combinators.hs b/src/Data/Either/Combinators.hs
--- a/src/Data/Either/Combinators.hs
+++ b/src/Data/Either/Combinators.hs
@@ -1,3 +1,4 @@
+{-# language CPP #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Data.Either.Combinators
@@ -36,7 +37,9 @@
   , swapEither
   ) where
 
+#if __GLASGOW_HASKELL__ < 710
 import Control.Applicative
+#endif
 import Control.Monad.Error.Class ( MonadError(throwError) )
 
 -- ---------------------------------------------------------------------------