diff --git a/.gitignore b/.gitignore
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 dist
+dist-newstyle
 docs
 wiki
 TAGS
@@ -11,3 +12,21 @@
 *.hi
 *~
 *#
+.stack-work/
+cabal-dev
+*.chi
+*.chs.h
+*.dyn_o
+*.dyn_hi
+.hpc
+.hsenv
+.cabal-sandbox/
+cabal.sandbox.config
+*.prof
+*.aux
+*.hp
+*.eventlog
+cabal.project.local
+cabal.project.local~
+.HTF/
+.ghc.environment.*
diff --git a/.travis.yml b/.travis.yml
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,15 @@
-language: haskell
+# This Travis job script has been generated by a script via
+#
+#   runghc make_travis_yml_2.hs '-o' '.travis.yml' '--irc-channel=irc.freenode.org#haskell-lens' '--no-no-tests-no-bench' '--no-installed' 'cabal.project'
+#
+# For more information, see https://github.com/hvr/multi-ghc-travis
+#
+language: c
+sudo: false
+
+git:
+  submodules: false  # whether to recursively clone submodules
+
 notifications:
   irc:
     channels:
@@ -6,3 +17,130 @@
     skip_join: true
     template:
       - "\x0313hybrid-vectors\x03/\x0306%{branch}\x03 \x0314%{commit}\x03 %{build_url} %{message}"
+
+cache:
+  directories:
+    - $HOME/.cabal/packages
+    - $HOME/.cabal/store
+
+before_cache:
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/build-reports.log
+  # remove files that are regenerated by 'cabal update'
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/00-index.*
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/*.json
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/01-index.cache
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/01-index.tar
+  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/01-index.tar.idx
+
+  - rm -rfv $HOME/.cabal/packages/head.hackage
+
+matrix:
+  include:
+    - compiler: "ghc-7.0.4"
+    # env: TEST=--disable-tests BENCH=--disable-benchmarks
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.0,ghc-7.0.4], sources: [hvr-ghc]}}
+    - compiler: "ghc-7.2.2"
+    # env: TEST=--disable-tests BENCH=--disable-benchmarks
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.0,ghc-7.2.2], sources: [hvr-ghc]}}
+    - compiler: "ghc-7.4.2"
+    # env: TEST=--disable-tests BENCH=--disable-benchmarks
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.0,ghc-7.4.2], sources: [hvr-ghc]}}
+    - compiler: "ghc-7.6.3"
+    # env: TEST=--disable-tests BENCH=--disable-benchmarks
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.0,ghc-7.6.3], sources: [hvr-ghc]}}
+    - compiler: "ghc-7.8.4"
+    # env: TEST=--disable-tests BENCH=--disable-benchmarks
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.0,ghc-7.8.4], sources: [hvr-ghc]}}
+    - compiler: "ghc-7.10.3"
+    # env: TEST=--disable-tests BENCH=--disable-benchmarks
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.0,ghc-7.10.3], sources: [hvr-ghc]}}
+    - compiler: "ghc-8.0.2"
+    # env: TEST=--disable-tests BENCH=--disable-benchmarks
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.0,ghc-8.0.2], sources: [hvr-ghc]}}
+    - compiler: "ghc-8.2.2"
+    # env: TEST=--disable-tests BENCH=--disable-benchmarks
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.0,ghc-8.2.2], sources: [hvr-ghc]}}
+    - compiler: "ghc-8.4.1"
+      env: GHCHEAD=true
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-head,ghc-8.4.1], sources: [hvr-ghc]}}
+    - compiler: "ghc-head"
+      env: GHCHEAD=true
+      addons: {apt: {packages: [ghc-ppa-tools,cabal-install-head,ghc-head], sources: [hvr-ghc]}}
+
+  allow_failures:
+    - compiler: "ghc-7.0.4"
+    - compiler: "ghc-7.2.2"
+    - compiler: "ghc-8.4.1"
+    - compiler: "ghc-head"
+
+before_install:
+  - HC=${CC}
+  - HCPKG=${HC/ghc/ghc-pkg}
+  - unset CC
+  - ROOTDIR=$(pwd)
+  - mkdir -p $HOME/.local/bin
+  - "PATH=/opt/ghc/bin:/opt/ghc-ppa-tools/bin:$HOME/local/bin:$PATH"
+  - HCNUMVER=$(( $(${HC} --numeric-version|sed -E 's/([0-9]+)\.([0-9]+)\.([0-9]+).*/\1 * 10000 + \2 * 100 + \3/') ))
+  - echo $HCNUMVER
+
+install:
+  - cabal --version
+  - echo "$(${HC} --version) [$(${HC} --print-project-git-commit-id 2> /dev/null || echo '?')]"
+  - BENCH=${BENCH---enable-benchmarks}
+  - TEST=${TEST---enable-tests}
+  - HADDOCK=${HADDOCK-true}
+  - INSTALLED=${INSTALLED-true}
+  - GHCHEAD=${GHCHEAD-false}
+  - travis_retry cabal update -v
+  - "sed -i.bak 's/^jobs:/-- jobs:/' ${HOME}/.cabal/config"
+  - rm -fv cabal.project cabal.project.local
+  # Overlay Hackage Package Index for GHC HEAD: https://github.com/hvr/head.hackage
+  - |
+    if $GHCHEAD; then
+      sed -i.bak 's/-- allow-newer:.*/allow-newer: *:base, *:template-haskell, *:ghc, *:Cabal/' ${HOME}/.cabal/config
+
+      echo 'repository head.hackage'                                                        >> ${HOME}/.cabal/config
+      echo '   url: http://head.hackage.haskell.org/'                                       >> ${HOME}/.cabal/config
+      echo '   secure: True'                                                                >> ${HOME}/.cabal/config
+      echo '   root-keys: 07c59cb65787dedfaef5bd5f987ceb5f7e5ebf88b904bbd4c5cbdeb2ff71b740' >> ${HOME}/.cabal/config
+      echo '              2e8555dde16ebd8df076f1a8ef13b8f14c66bad8eafefd7d9e37d0ed711821fb' >> ${HOME}/.cabal/config
+      echo '              8f79fd2389ab2967354407ec852cbe73f2e8635793ac446d09461ffb99527f6e' >> ${HOME}/.cabal/config
+      echo '   key-threshold: 3'                                                            >> ${HOME}/.cabal.config
+
+      cabal new-update head.hackage -v
+    fi
+  - grep -Ev -- '^\s*--' ${HOME}/.cabal/config | grep -Ev '^\s*$'
+  - "printf 'packages: \".\"\\n' > cabal.project"
+  - cat cabal.project
+  - if [ -f "./configure.ac" ]; then
+      (cd "." && autoreconf -i);
+    fi
+  - rm -f cabal.project.freeze
+  - cabal new-build -w ${HC} ${TEST} ${BENCH} --project-file="cabal.project" --dep -j2 all
+  - rm -rf "."/.ghc.environment.* "."/dist
+  - DISTDIR=$(mktemp -d /tmp/dist-test.XXXX)
+
+# 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:
+  # test that source-distributions can be generated
+  - (cd "." && cabal sdist)
+  - mv "."/dist/hybrid-vectors-*.tar.gz ${DISTDIR}/
+  - cd ${DISTDIR} || false
+  - find . -maxdepth 1 -name '*.tar.gz' -exec tar -xvf '{}' \;
+  - "printf 'packages: hybrid-vectors-*/*.cabal\\n' > cabal.project"
+  - cat cabal.project
+
+
+  # build & run tests, build benchmarks
+  - cabal new-build -w ${HC} ${TEST} ${BENCH} all
+
+  # cabal check
+  - (cd hybrid-vectors-* && cabal check)
+
+  # haddock
+  - rm -rf ./dist-newstyle
+  - if $HADDOCK; then cabal new-haddock -w ${HC} ${TEST} ${BENCH} all; else echo "Skipping haddock generation";fi
+
+# REGENDATA ["-o",".travis.yml","--irc-channel=irc.freenode.org#haskell-lens","--no-no-tests-no-bench","--no-installed","cabal.project"]
+# EOF
diff --git a/hybrid-vectors.cabal b/hybrid-vectors.cabal
--- a/hybrid-vectors.cabal
+++ b/hybrid-vectors.cabal
@@ -1,6 +1,6 @@
 name:          hybrid-vectors
 category:      Data, Vector
-version:       0.2.1
+version:       0.2.2
 license:       BSD3
 cabal-version: >= 1.6
 license-file:  LICENSE
@@ -17,7 +17,16 @@
   .travis.yml
   .gitignore
   .vim.custom
-description: Hybrid vectors e.g. Mixed Boxed/Unboxed vectors
+description: Hybrid vectors e.g. Mixed Boxed/Unboxed vectors.
+tested-with:   GHC == 7.0.4
+             , GHC == 7.2.2
+             , GHC == 7.4.2
+             , GHC == 7.6.3
+             , GHC == 7.8.4
+             , GHC == 7.10.3
+             , GHC == 8.0.2
+             , GHC == 8.2.2
+             , GHC == 8.4.1
 
 source-repository head
   type: git
@@ -28,7 +37,8 @@
     base          >= 4       && < 5,
     deepseq       >= 1.1     && < 1.5,
     primitive     >= 0.5     && < 0.7,
-    vector        >= 0.10    && < 0.12
+    vector        >= 0.10    && < 0.13,
+    semigroups    >= 0.9     && < 1
 
   hs-source-dirs: src
 
diff --git a/src/Data/Vector/Hybrid/Internal.hs b/src/Data/Vector/Hybrid/Internal.hs
--- a/src/Data/Vector/Hybrid/Internal.hs
+++ b/src/Data/Vector/Hybrid/Internal.hs
@@ -1,13 +1,7 @@
-{-# LANGUAGE CPP #-}
-{-# LANGUAGE GeneralizedNewtypeDeriving #-}
-{-# LANGUAGE KindSignatures #-}
-{-# LANGUAGE GADTs #-}
-{-# LANGUAGE MultiParamTypeClasses #-}
-{-# LANGUAGE UndecidableInstances #-}
-{-# LANGUAGE FlexibleInstances #-}
-{-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE DeriveDataTypeable #-}
-{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE CPP, DeriveDataTypeable, FlexibleInstances, GADTs        #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving, KindSignatures               #-}
+{-# LANGUAGE MultiParamTypeClasses, ScopedTypeVariables, TypeFamilies #-}
+{-# LANGUAGE UndecidableInstances                                     #-}
 
 #ifndef MIN_VERSION_base
 #define MIN_VERSION_base(x,y,z) 1
@@ -22,10 +16,12 @@
   , Vector(..)
   ) where
 
-import Control.Monad
-import Data.Monoid
+import           Control.Monad
+import qualified Data.Foldable               as F
+import           Data.Monoid
+import           Data.Semigroup
+import qualified Data.Vector.Generic         as G
 import qualified Data.Vector.Generic.Mutable as GM
-import qualified Data.Vector.Generic as G
 
 
 #if MIN_VERSION_vector(0,11,0)
@@ -35,7 +31,8 @@
 #endif
 
 import Data.Data
-import Prelude hiding ( length, null, replicate, reverse, map, read, take, drop, init, tail )
+import Prelude   hiding (drop, init, length, map, null, read, replicate,
+                  reverse, tail, take)
 import Text.Read
 
 data MVector :: (* -> * -> *) -> (* -> * -> *) -> * -> * -> * where
@@ -141,6 +138,10 @@
   {-# INLINE basicUnsafeCopy #-}
   elemseq (V ks vs) (k,v) b = G.elemseq ks k (G.elemseq vs v b)
   {-# INLINE elemseq #-}
+
+instance (G.Vector u a, G.Vector v b, c ~ (a, b)) => Semigroup (Vector u v c) where
+  (<>) = mappend
+  sconcat = mconcat . F.toList
 
 instance (G.Vector u a, G.Vector v b, c ~ (a, b)) => Monoid (Vector u v c) where
   mappend = (G.++)
