diff --git a/.travis.yml b/.travis.yml
index 9e8fc17..609c217 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -20,68 +20,66 @@ cache:
     - $HOME/.cabal/store
 
 before_cache:
-  - rm -fv $HOME/.cabal/packages/hackage.haskell.org/build-reports.log
+  - rm -fv $CABALHOME/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 -fv $CABALHOME/packages/hackage.haskell.org/00-index.*
+  - rm -fv $CABALHOME/packages/hackage.haskell.org/*.json
+  - rm -fv $CABALHOME/packages/hackage.haskell.org/01-index.cache
+  - rm -fv $CABALHOME/packages/hackage.haskell.org/01-index.tar
+  - rm -fv $CABALHOME/packages/hackage.haskell.org/01-index.tar.idx
 
-  - rm -rfv $HOME/.cabal/packages/head.hackage
+  - rm -rfv $CABALHOME/packages/head.hackage
 
 matrix:
   include:
     - compiler: "ghc-8.6.3"
-    # env: TEST=--disable-tests BENCH=--disable-benchmarks
       addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.4,ghc-8.6.3], sources: [hvr-ghc]}}
     - compiler: "ghc-8.4.4"
-    # env: TEST=--disable-tests BENCH=--disable-benchmarks
       addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.4,ghc-8.4.4], sources: [hvr-ghc]}}
     - compiler: "ghc-8.2.2"
-    # env: TEST=--disable-tests BENCH=--disable-benchmarks
       addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.4,ghc-8.2.2], sources: [hvr-ghc]}}
     - compiler: "ghc-8.0.2"
-    # env: TEST=--disable-tests BENCH=--disable-benchmarks
       addons: {apt: {packages: [ghc-ppa-tools,cabal-install-2.4,ghc-8.0.2], sources: [hvr-ghc]}}
 
 before_install:
-  - HC=${CC}
+  - HC=/opt/ghc/bin/${CC}
+  - HCVER=$(echo "$TRAVIS_COMPILER" | sed 's/ghc-//')
+  - echo $HCVER
   - HCPKG=${HC/ghc/ghc-pkg}
   - unset CC
+  - CABAL=/opt/ghc/bin/cabal
+  - CABALHOME=$HOME/.cabal
+  - export PATH="$CABALHOME/bin:$PATH"
   - ROOTDIR=$(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
+  - ${CABAL} --version
   - echo "$(${HC} --version) [$(${HC} --print-project-git-commit-id 2> /dev/null || echo '?')]"
-  - BENCH=${BENCH---enable-benchmarks}
-  - TEST=${TEST---enable-tests}
-  - HADDOCK=${HADDOCK-true}
-  - UNCONSTRAINED=${UNCONSTRAINED-true}
-  - NOINSTALLEDCONSTRAINTS=${NOINSTALLEDCONSTRAINTS-false}
+  - TEST=--enable-tests
+  - BENCH=--enable-benchmarks
   - GHCHEAD=${GHCHEAD-false}
-  - travis_retry cabal update -v
-  - "sed -i.bak 's/^jobs:/-- jobs:/' ${HOME}/.cabal/config"
+  - if [ "$TRAVIS_OS_NAME" = "windows" ]; then export CABALHOME=$APPDATA/cabal; else export CABALHOME=$HOME/.cabal; fi
+  - travis_retry ${CABAL} update -v
+  - sed -i.bak 's/^jobs:/-- jobs:/' $CABALHOME/config
   - rm -fv cabal.project cabal.project.local
-  - grep -Ev -- '^\s*--' ${HOME}/.cabal/config | grep -Ev '^\s*$'
-  - "printf 'packages: \".\"\\n' > cabal.project"
+  - grep -Ev -- '^\s*--' $CABALHOME/config | grep -Ev '^\s*$'
+  - rm -f cabal.project
+  - touch cabal.project
+  - "printf 'packages: \".\"\\n' >> cabal.project"
   - "printf 'write-ghc-environment-files: always\\n' >> cabal.project"
-  - "echo 'reorder-goals: True' >> cabal.project"
-  - "echo 'max-backjumps: 100' >> cabal.project"
   - touch cabal.project.local
-  - "if ! $NOINSTALLEDCONSTRAINTS; then for pkg in $($HCPKG list --simple-output); do echo $pkg  | grep -vw -- servant-ekg | sed 's/^/constraints: /' | sed 's/-[^-]*$/ installed/' >> cabal.project.local; done; fi"
+  - "for pkg in $($HCPKG list --simple-output); do echo $pkg | sed 's/-[^-]*$//' | grep -vE -- '^(servant-ekg)$' | sed 's/^/constraints: /' | sed 's/$/ installed/' >> cabal.project.local; done"
   - cat cabal.project || true
   - cat cabal.project.local || true
-  - if [ -f "./configure.ac" ]; then
-      (cd "." && autoreconf -i);
-    fi
+  - 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
-  - cabal new-build -w ${HC} --disable-tests --disable-benchmarks --project-file="cabal.project" --dep -j2 all
+  - ${CABAL} new-freeze -w ${HC} ${TEST} ${BENCH} --project-file="cabal.project" --dry
+  - "cat \"cabal.project.freeze\" | sed -E 's/^(constraints: *| *)//' | sed 's/any.//'"
+  - rm  "cabal.project.freeze"
+  - ${CABAL} new-build -w ${HC} ${TEST} ${BENCH} --project-file="cabal.project" --dep -j2 all
+  - ${CABAL} new-build -w ${HC} --disable-tests --disable-benchmarks --project-file="cabal.project" --dep -j2 all
   - rm -rf .ghc.environment.* "."/dist
   - DISTDIR=$(mktemp -d /tmp/dist-test.XXXX)
 
@@ -89,33 +87,33 @@ install:
 # any command which exits with a non-zero exit code causes the build to fail.
 script:
   # test that source-distributions can be generated
-  - cabal new-sdist all
+  - ${CABAL} new-sdist all
   - mv dist-newstyle/sdist/*.tar.gz ${DISTDIR}/
   - cd ${DISTDIR} || false
   - find . -maxdepth 1 -name '*.tar.gz' -exec tar -xvf '{}' \;
-  - "printf 'packages: servant-ekg-*/*.cabal\\n' > cabal.project"
+  - rm -f cabal.project
+  - touch cabal.project
+  - "printf 'packages: \"servant-ekg-*/*.cabal\"\\n' >> cabal.project"
   - "printf 'write-ghc-environment-files: always\\n' >> cabal.project"
-  - "echo 'reorder-goals: True' >> cabal.project"
-  - "echo 'max-backjumps: 100' >> cabal.project"
   - touch cabal.project.local
-  - "if ! $NOINSTALLEDCONSTRAINTS; then for pkg in $($HCPKG list --simple-output); do echo $pkg  | grep -vw -- servant-ekg | sed 's/^/constraints: /' | sed 's/-[^-]*$/ installed/' >> cabal.project.local; done; fi"
+  - "for pkg in $($HCPKG list --simple-output); do echo $pkg | sed 's/-[^-]*$//' | grep -vE -- '^(servant-ekg)$' | sed 's/^/constraints: /' | sed 's/$/ installed/' >> cabal.project.local; done"
   - cat cabal.project || true
   - cat cabal.project.local || true
   # this builds all libraries and executables (without tests/benchmarks)
-  - cabal new-build -w ${HC} --disable-tests --disable-benchmarks all
+  - ${CABAL} new-build -w ${HC} --disable-tests --disable-benchmarks all
 
   # build & run tests, build benchmarks
-  - cabal new-build -w ${HC} ${TEST} ${BENCH} all
-  - if [ "x$TEST" = "x--enable-tests" ]; then cabal new-test -w ${HC} ${TEST} ${BENCH} all; fi
+  - ${CABAL} new-build -w ${HC} ${TEST} ${BENCH} all
+  - if [ "x$TEST" = "x--enable-tests" ]; then ${CABAL} new-test -w ${HC} ${TEST} ${BENCH} all; fi
 
   # cabal check
-  - (cd servant-ekg-* && cabal check)
+  - (cd servant-ekg-* && ${CABAL} check)
 
   # haddock
-  - if $HADDOCK; then cabal new-haddock -w ${HC} ${TEST} ${BENCH} all; else echo "Skipping haddock generation";fi
+  - ${CABAL} new-haddock -w ${HC} ${TEST} ${BENCH} all
 
   # Build without installed constraints for packages in global-db
-  - if $UNCONSTRAINED; then rm -f cabal.project.local; cabal new-build -w ${HC} --disable-tests --disable-benchmarks all; else echo "Not building without installed constraints"; fi
+  - rm -f cabal.project.local; ${CABAL} new-build -w ${HC} --disable-tests --disable-benchmarks all;
 
 # REGENDATA ["--output=.travis.yml","--branches=master","cabal.project"]
 # EOF
diff --git a/cabal.project b/cabal.project
index 3d5fac9..e6fdbad 100644
--- a/cabal.project
+++ b/cabal.project
@@ -1,3 +1 @@
 packages: .
-reorder-goals: True
-max-backjumps: 100
diff --git a/servant-ekg.cabal b/servant-ekg.cabal
index 7cc85fa..76bfac3 100644
--- a/servant-ekg.cabal
+++ b/servant-ekg.cabal
@@ -26,7 +26,7 @@ library
       base                  >=4.9      && <4.13
     , ekg-core              >=0.1.1.6  && <0.2
     , http-types            >=0.12.2   && <0.13
-    , servant               >=0.15     && <0.16
+    , servant               >=0.15     && <0.17
     , text                  >=1.2.3.0  && <1.3
     , time                  >=1.6.0.1  && <1.9
     , unordered-containers  >=0.2.9.0  && <0.3
diff --git a/test/Servant/EkgSpec.hs b/test/Servant/EkgSpec.hs
index 686ba4e..86848c8 100644
--- a/test/Servant/EkgSpec.hs
+++ b/test/Servant/EkgSpec.hs
@@ -27,6 +27,9 @@ import           Test.Hspec
 
 import           Servant.Ekg
 
+#if !MIN_VERSION_servant_client(0,16,0)
+#define ClientError ServantError
+#endif
 
 -- * Spec
 
@@ -38,7 +41,7 @@ spec = describe "servant-ekg" $ do
   it "collects number of request" $ do
     withApp $ \port mvar -> do
       mgr <- newManager defaultManagerSettings
-      let runFn :: ClientM a -> IO (Either ServantError a)
+      let runFn :: ClientM a -> IO (Either ClientError a)
           runFn fn = runClientM fn (mkClientEnv mgr (BaseUrl Http "localhost" port ""))
       _ <- runFn $ getEp "name" Nothing
       _ <- runFn $ postEp (Greet "hi")