diff --git a/.travis.yml b/.travis.yml
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,9 +2,13 @@
 #
 #   haskell-ci '--output=.travis.yml' '--config=cabal.haskell-ci' 'cabal.project'
 #
+# To regenerate the script (for example after adjusting tested-with) run
+#
+#   haskell-ci regenerate
+#
 # For more information, see https://github.com/haskell-CI/haskell-ci
 #
-# version: 0.9.20191126
+# version: 0.10
 #
 version: ~> 1.0
 language: c
@@ -19,7 +23,7 @@
       - irc.freenode.org#haskell-lens
     skip_join: true
     template:
-      - "\"\\x0313free\\x03/\\x0306%{branch}\\x03 \\x0314%{commit}\\x03 %{build_url} %{message}\""
+      - "\x0313free\x03/\x0306%{branch}\x03 \x0314%{commit}\x03 %{build_url} %{message}"
 cache:
   directories:
     - $HOME/.cabal/packages
@@ -37,41 +41,35 @@
 jobs:
   include:
     - compiler: ghc-8.10.1
-      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-8.10.1","cabal-install-3.0"]}}
+      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-8.10.1","cabal-install-3.2"]}}
       os: linux
-    - compiler: ghc-8.8.1
-      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-8.8.1","cabal-install-3.0"]}}
+    - compiler: ghc-8.8.3
+      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-8.8.3","cabal-install-3.2"]}}
       os: linux
     - compiler: ghc-8.6.5
-      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-8.6.5","cabal-install-3.0"]}}
+      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-8.6.5","cabal-install-3.2"]}}
       os: linux
     - compiler: ghc-8.4.4
-      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-8.4.4","cabal-install-3.0"]}}
+      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-8.4.4","cabal-install-3.2"]}}
       os: linux
     - compiler: ghc-8.2.2
-      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-8.2.2","cabal-install-3.0"]}}
+      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-8.2.2","cabal-install-3.2"]}}
       os: linux
     - compiler: ghc-8.0.2
-      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-8.0.2","cabal-install-3.0"]}}
+      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-8.0.2","cabal-install-3.2"]}}
       os: linux
     - compiler: ghc-7.10.3
-      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-7.10.3","cabal-install-3.0"]}}
+      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-7.10.3","cabal-install-3.2"]}}
       os: linux
     - compiler: ghc-7.8.4
-      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-7.8.4","cabal-install-3.0"]}}
+      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-7.8.4","cabal-install-3.2"]}}
       os: linux
     - compiler: ghc-7.6.3
-      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-7.6.3","cabal-install-3.0"]}}
+      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-7.6.3","cabal-install-3.2"]}}
       os: linux
     - compiler: ghc-7.4.2
-      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-7.4.2","cabal-install-3.0"]}}
-      os: linux
-    - compiler: ghc-head
-      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-head","cabal-install-head"]}}
+      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu xenial main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-7.4.2","cabal-install-3.2"]}}
       os: linux
-  allow_failures:
-    - compiler: ghc-head
-    - compiler: ghc-8.10.1
 before_install:
   - HC=$(echo "/opt/$CC/bin/ghc" | sed 's/-/\//')
   - WITHCOMPILER="-w $HC"
@@ -84,69 +82,31 @@
   - TOP=$(pwd)
   - "HCNUMVER=$(${HC} --numeric-version|perl -ne '/^(\\d+)\\.(\\d+)\\.(\\d+)(\\.(\\d+))?$/; print(10000 * $1 + 100 * $2 + ($3 == 0 ? $5 != 1 : $3))')"
   - echo $HCNUMVER
-  - CABAL="$CABAL -vnormal+nowrap+markoutput"
+  - CABAL="$CABAL -vnormal+nowrap"
   - set -o pipefail
-  - |
-    echo 'function blue(s) { printf "\033[0;34m" s "\033[0m " }'           >> .colorful.awk
-    echo 'BEGIN { state = "output"; }'                                     >> .colorful.awk
-    echo '/^-----BEGIN CABAL OUTPUT-----$/ { state = "cabal" }'            >> .colorful.awk
-    echo '/^-----END CABAL OUTPUT-----$/ { state = "output" }'             >> .colorful.awk
-    echo '!/^(-----BEGIN CABAL OUTPUT-----|-----END CABAL OUTPUT-----)/ {' >> .colorful.awk
-    echo '  if (state == "cabal") {'                                       >> .colorful.awk
-    echo '    print blue($0)'                                              >> .colorful.awk
-    echo '  } else {'                                                      >> .colorful.awk
-    echo '    print $0'                                                    >> .colorful.awk
-    echo '  }'                                                             >> .colorful.awk
-    echo '}'                                                               >> .colorful.awk
-  - cat .colorful.awk
-  - |
-    color_cabal_output () {
-      awk -f $TOP/.colorful.awk
-    }
-  - echo text | color_cabal_output
-install:
-  - ${CABAL} --version
-  - echo "$(${HC} --version) [$(${HC} --print-project-git-commit-id 2> /dev/null || echo '?')]"
   - TEST=--enable-tests
   - BENCH=--enable-benchmarks
   - HEADHACKAGE=false
-  - if [ $HCNUMVER -ge 81000 ] ; then HEADHACKAGE=true ; fi
   - rm -f $CABALHOME/config
   - |
-    echo "verbose: normal +nowrap +markoutput"                                  >> $CABALHOME/config
-    echo "remote-build-reporting: anonymous"                                    >> $CABALHOME/config
-    echo "write-ghc-environment-files: always"                                  >> $CABALHOME/config
-    echo "remote-repo-cache: $CABALHOME/packages"                               >> $CABALHOME/config
-    echo "logs-dir:          $CABALHOME/logs"                                   >> $CABALHOME/config
-    echo "world-file:        $CABALHOME/world"                                  >> $CABALHOME/config
-    echo "extra-prog-path:   $CABALHOME/bin"                                    >> $CABALHOME/config
-    echo "symlink-bindir:    $CABALHOME/bin"                                    >> $CABALHOME/config
-    echo "installdir:        $CABALHOME/bin"                                    >> $CABALHOME/config
-    echo "build-summary:     $CABALHOME/logs/build.log"                         >> $CABALHOME/config
-    echo "store-dir:         $CABALHOME/store"                                  >> $CABALHOME/config
-    echo "install-dirs user"                                                    >> $CABALHOME/config
-    echo "  prefix: $CABALHOME"                                                 >> $CABALHOME/config
-    echo "repository hackage.haskell.org"                                       >> $CABALHOME/config
-    echo "  url: http://hackage.haskell.org/"                                   >> $CABALHOME/config
-    echo "  secure: True"                                                       >> $CABALHOME/config
-    echo "  key-threshold: 3"                                                   >> $CABALHOME/config
-    echo "  root-keys:"                                                         >> $CABALHOME/config
-    echo "    fe331502606802feac15e514d9b9ea83fee8b6ffef71335479a2e68d84adc6b0" >> $CABALHOME/config
-    echo "    1ea9ba32c526d1cc91ab5e5bd364ec5e9e8cb67179a471872f6e26f0ae773d42" >> $CABALHOME/config
-    echo "    2c6c3627bd6c982990239487f1abd02e08a02e6cf16edb105a8012d444d870c3" >> $CABALHOME/config
-    echo "    0a5c7ea47cd1b15f01f5f51a33adda7e655bc0f0b0615baa8e271f4c3351e21d" >> $CABALHOME/config
-    echo "    51f0161b906011b52c6613376b1ae937670da69322113a246a09f807c62f6921" >> $CABALHOME/config
-  - |
-    if $HEADHACKAGE; then
-    echo "allow-newer: $($HCPKG list --simple-output | sed -E 's/([a-zA-Z-]+)-[0-9.]+/*:\1/g')" >> $CABALHOME/config
-    echo "repository head.hackage.ghc.haskell.org"                                        >> $CABALHOME/config
-    echo "   url: https://ghc.gitlab.haskell.org/head.hackage/"                           >> $CABALHOME/config
-    echo "   secure: True"                                                                >> $CABALHOME/config
-    echo "   root-keys: 7541f32a4ccca4f97aea3b22f5e593ba2c0267546016b992dfadcd2fe944e55d" >> $CABALHOME/config
-    echo "              26021a13b401500c8eb2761ca95c61f2d625bfef951b939a8124ed12ecf07329" >> $CABALHOME/config
-    echo "              f76d08be13e9a61a377a85e2fb63f4c5435d40f8feb3e12eb05905edb8cdea89" >> $CABALHOME/config
-    echo "   key-threshold: 3"                                                            >> $CABALHOME/config
-    fi
+    echo "verbose: normal +nowrap +markoutput"          >> $CABALHOME/config
+    echo "remote-build-reporting: anonymous"            >> $CABALHOME/config
+    echo "write-ghc-environment-files: always"          >> $CABALHOME/config
+    echo "remote-repo-cache: $CABALHOME/packages"       >> $CABALHOME/config
+    echo "logs-dir:          $CABALHOME/logs"           >> $CABALHOME/config
+    echo "world-file:        $CABALHOME/world"          >> $CABALHOME/config
+    echo "extra-prog-path:   $CABALHOME/bin"            >> $CABALHOME/config
+    echo "symlink-bindir:    $CABALHOME/bin"            >> $CABALHOME/config
+    echo "installdir:        $CABALHOME/bin"            >> $CABALHOME/config
+    echo "build-summary:     $CABALHOME/logs/build.log" >> $CABALHOME/config
+    echo "store-dir:         $CABALHOME/store"          >> $CABALHOME/config
+    echo "install-dirs user"                            >> $CABALHOME/config
+    echo "  prefix: $CABALHOME"                         >> $CABALHOME/config
+    echo "repository hackage.haskell.org"               >> $CABALHOME/config
+    echo "  url: http://hackage.haskell.org/"           >> $CABALHOME/config
+install:
+  - ${CABAL} --version
+  - echo "$(${HC} --version) [$(${HC} --print-project-git-commit-id 2> /dev/null || echo '?')]"
   - |
     echo "program-default-options"                >> $CABALHOME/config
     echo "  ghc-options: $GHCJOBS +RTS -M6G -RTS" >> $CABALHOME/config
@@ -159,6 +119,10 @@
   - |
     echo "packages: ." >> cabal.project
     echo "packages: ./examples" >> cabal.project
+  - if [ $HCNUMVER -ge 80200 ] ; then echo 'package free' >> cabal.project ; fi
+  - "if [ $HCNUMVER -ge 80200 ] ; then echo '  ghc-options: -Werror=missing-methods' >> cabal.project ; fi"
+  - if [ $HCNUMVER -ge 80200 ] ; then echo 'package free-examples' >> cabal.project ; fi
+  - "if [ $HCNUMVER -ge 80200 ] ; then echo '  ghc-options: -Werror=missing-methods' >> cabal.project ; fi"
   - |
     echo "package free-examples"     >> cabal.project
     echo "  flags: -mandelbrot-iter" >> cabal.project
@@ -167,14 +131,14 @@
   - cat cabal.project.local || true
   - if [ -f "./configure.ac" ]; then (cd "." && autoreconf -i); fi
   - if [ -f "./examples/configure.ac" ]; then (cd "./examples" && autoreconf -i); fi
-  - ${CABAL} v2-freeze $WITHCOMPILER ${TEST} ${BENCH} | color_cabal_output
+  - ${CABAL} v2-freeze $WITHCOMPILER ${TEST} ${BENCH}
   - "cat cabal.project.freeze | sed -E 's/^(constraints: *| *)//' | sed 's/any.//'"
   - rm  cabal.project.freeze
-  - ${CABAL} v2-build $WITHCOMPILER ${TEST} ${BENCH} --dep -j2 all | color_cabal_output
+  - travis_wait 40 ${CABAL} v2-build $WITHCOMPILER ${TEST} ${BENCH} --dep -j2 all
 script:
   - DISTDIR=$(mktemp -d /tmp/dist-test.XXXX)
   # Packaging...
-  - ${CABAL} v2-sdist all | color_cabal_output
+  - ${CABAL} v2-sdist all
   # Unpacking...
   - mv dist-newstyle/sdist/*.tar.gz ${DISTDIR}/
   - cd ${DISTDIR} || false
@@ -188,6 +152,10 @@
   - |
     echo "packages: ${PKGDIR_free}" >> cabal.project
     echo "packages: ${PKGDIR_free_examples}" >> cabal.project
+  - if [ $HCNUMVER -ge 80200 ] ; then echo 'package free' >> cabal.project ; fi
+  - "if [ $HCNUMVER -ge 80200 ] ; then echo '  ghc-options: -Werror=missing-methods' >> cabal.project ; fi"
+  - if [ $HCNUMVER -ge 80200 ] ; then echo 'package free-examples' >> cabal.project ; fi
+  - "if [ $HCNUMVER -ge 80200 ] ; then echo '  ghc-options: -Werror=missing-methods' >> cabal.project ; fi"
   - |
     echo "package free-examples"     >> cabal.project
     echo "  flags: -mandelbrot-iter" >> cabal.project
@@ -196,12 +164,12 @@
   - cat cabal.project.local || true
   # Building with tests and benchmarks...
   # build & run tests, build benchmarks
-  - ${CABAL} v2-build $WITHCOMPILER ${TEST} ${BENCH} all | color_cabal_output
+  - ${CABAL} v2-build $WITHCOMPILER ${TEST} ${BENCH} all
   # cabal check...
   - (cd ${PKGDIR_free} && ${CABAL} -vnormal check)
   - (cd ${PKGDIR_free_examples} && ${CABAL} -vnormal check)
   # haddock...
-  - ${CABAL} v2-haddock $WITHCOMPILER --with-haddock $HADDOCK ${TEST} ${BENCH} all | color_cabal_output
+  - ${CABAL} v2-haddock $WITHCOMPILER --with-haddock $HADDOCK ${TEST} ${BENCH} all
 
-# REGENDATA ("0.9.20191126",["--output=.travis.yml","--config=cabal.haskell-ci","cabal.project"])
+# REGENDATA ("0.10",["--output=.travis.yml","--config=cabal.haskell-ci","cabal.project"])
 # EOF
diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+5.1.4 [2020.10.01]
+------------------
+* Allow building with `template-haskell-2.17.0.0` (GHC 9.0).
+
 5.1.3 [2019.11.26]
 ------------------
 * Allow building with `template-haskell-2.16` (GHC 8.10).
diff --git a/doc/proof/Control/Comonad/Trans/Cofree/instance-Applicative-CofreeT.md b/doc/proof/Control/Comonad/Trans/Cofree/instance-Applicative-CofreeT.md
--- a/doc/proof/Control/Comonad/Trans/Cofree/instance-Applicative-CofreeT.md
+++ b/doc/proof/Control/Comonad/Trans/Cofree/instance-Applicative-CofreeT.md
@@ -200,7 +200,7 @@
 .               ≡ (.)
 ```
 
-By repeteadly applying the Applicative laws for the underlying functor, we
+By repeatedly applying the Applicative laws for the underlying functor, we
 get:
 
 ```haskell
@@ -288,7 +288,7 @@
 $W              ≡ ($ star(C w))
 ```
 
-By repeteadly applying composition law for w, we get:
+By repeatedly applying composition law for w, we get:
 
 ```haskell
   
diff --git a/doc/proof/Control/Comonad/Trans/Cofree/instance-Monad-CofreeT.md b/doc/proof/Control/Comonad/Trans/Cofree/instance-Monad-CofreeT.md
--- a/doc/proof/Control/Comonad/Trans/Cofree/instance-Monad-CofreeT.md
+++ b/doc/proof/Control/Comonad/Trans/Cofree/instance-Monad-CofreeT.md
@@ -20,7 +20,7 @@
 This definition is equivalent to that of the Cofree module if 'w' is
 identity. 
 
-The tokens `CofreeT` and `runCofreeT` are abreviated as `C` and `unC`, 
+The tokens `CofreeT` and `runCofreeT` are abbreviated as `C` and `unC`, 
 respectively, for readability.
 
 ## Left identity
diff --git a/examples/MandelbrotIter.lhs b/examples/MandelbrotIter.lhs
--- a/examples/MandelbrotIter.lhs
+++ b/examples/MandelbrotIter.lhs
@@ -1,18 +1,15 @@
-Compiling to an executable file with the @-O2@ optimization level is recomended.
+Compiling to an executable file with the @-O2@ optimization level is recommended.
 
 For example: @ghc -o 'mandelbrot_iter' -O2 MandelbrotIter.lhs ; ./mandelbrot_iter@
 
 > {-# LANGUAGE PackageImports #-}
 
-> import Control.Arrow
+> import Control.Arrow hiding (loop)
 > import Control.Monad.Trans.Iter
 > import "mtl" Control.Monad.Reader
-> import "mtl" Control.Monad.List
-> import "mtl" Control.Monad.Identity
-> import Control.Monad.IO.Class
 > import Data.Complex
 > import Graphics.HGL (runGraphics, Window, withPen,
->                      line, RGB (RGB), RedrawMode (Unbuffered, DoubleBuffered), openWindowEx,
+>                      line, RGB (RGB), RedrawMode (DoubleBuffered), openWindowEx,
 >                      drawInWindow, mkPen, Style (Solid))
 
 Some fractals can be defined by infinite sequences of complex numbers. For example,
@@ -20,11 +17,11 @@
 the following sequence is generated for each point @c@ in the complex plane:
 
 @
-z₀ = c      
+z₀ = c
 
-z₁ = z₀² + c       
+z₁ = z₀² + c
 
-z₂ = z₁² + c        
+z₂ = z₁² + c
 
 …
 @
@@ -96,7 +93,7 @@
 Drawing a point is equivalent to drawing a line of length one.
 
 > drawPoint :: RGB -> (Int,Int) -> FractalM ()
-> drawPoint color p@(x,y) = do
+> drawPoint color (x,y) = do
 >   w <- asks window
 >   let point = line (x,y) (x+1, y+1)
 >   liftIO $ drawInWindow w $ mkPen Solid 1 color (flip withPen point)
@@ -133,6 +130,6 @@
 >   runGraphics $ do
 >     w <- openWindowEx "Mandelbrot" Nothing (windowWidth, windowHeight) DoubleBuffered (Just 1)
 >     let canvas = Canvas windowWidth windowHeight w
->     runFractalM' 100 canvas drawMandelbrot
+>     _ <- runFractalM' 100 canvas drawMandelbrot
 >     putStrLn $ "Fin"
 
diff --git a/examples/free-examples.cabal b/examples/free-examples.cabal
--- a/examples/free-examples.cabal
+++ b/examples/free-examples.cabal
@@ -18,7 +18,7 @@
              , GHC == 8.2.2
              , GHC == 8.4.4
              , GHC == 8.6.5
-             , GHC == 8.8.1
+             , GHC == 8.8.3
              , GHC == 8.10.1
 synopsis:      Monads for free
 description:   Examples projects using @free@
diff --git a/free.cabal b/free.cabal
--- a/free.cabal
+++ b/free.cabal
@@ -1,6 +1,6 @@
 name:          free
 category:      Control, Monads
-version:       5.1.3
+version:       5.1.4
 license:       BSD3
 cabal-version: 1.18
 license-file:  LICENSE
@@ -18,7 +18,7 @@
              , GHC == 8.2.2
              , GHC == 8.4.4
              , GHC == 8.6.5
-             , GHC == 8.8.1
+             , GHC == 8.8.3
              , GHC == 8.10.1
 synopsis:      Monads for free
 description:
@@ -87,9 +87,10 @@
     mtl                  >= 2.0.1.0 && < 2.3,
     profunctors          >= 4 && < 6,
     semigroupoids        >= 4 && < 6,
+    th-abstraction       >= 0.4 && < 0.5,
     transformers         >= 0.2.0   && < 0.6,
     transformers-base    >= 0.4 && < 0.5,
-    template-haskell     >= 2.7.0.0 && < 3,
+    template-haskell     >= 2.7.0.0 && < 2.18,
     exceptions           >= 0.6 && < 0.11,
     containers           < 0.7
 
@@ -133,6 +134,9 @@
 
   -- See https://ghc.haskell.org/trac/ghc/wiki/Migration/8.0#base-4.9.0.0
   if impl(ghc >= 8.0)
-    ghc-options: -Wcompat -Wnoncanonical-monad-instances -Wnoncanonical-monadfail-instances
+    ghc-options: -Wcompat -Wnoncanonical-monad-instances
+
+    if !impl(ghc >= 8.8)
+      ghc-options: -Wnoncanonical-monadfail-instances
   else
     build-depends: fail == 4.9.*
diff --git a/src/Control/Comonad/Cofree.hs b/src/Control/Comonad/Cofree.hs
--- a/src/Control/Comonad/Cofree.hs
+++ b/src/Control/Comonad/Cofree.hs
@@ -91,7 +91,7 @@
 --
 -- For instance,
 --
--- * @'Cofree' 'Maybe'@ forms the a comonad for a non-empty list.
+-- * @'Cofree' 'Maybe'@ forms the comonad for a non-empty list.
 --
 -- * @'Cofree' ('Const' b)@ is a product.
 --
diff --git a/src/Control/Monad/Free/TH.hs b/src/Control/Monad/Free/TH.hs
--- a/src/Control/Monad/Free/TH.hs
+++ b/src/Control/Monad/Free/TH.hs
@@ -36,7 +36,8 @@
 import Control.Monad
 import Data.Char (toLower)
 import Data.List ((\\), nub)
-import Language.Haskell.TH
+import Language.Haskell.TH.Datatype.TyVarBndr
+import Language.Haskell.TH.Ppr (pprint)
 import Language.Haskell.TH.Syntax
 
 #if !(MIN_VERSION_base(4,8,0))
@@ -63,10 +64,6 @@
 zipExprs ps (c:cs) (Captured _ _ : as) = c : zipExprs ps cs as
 zipExprs _ _ _ = []
 
-tyVarBndrName :: TyVarBndr -> Name
-tyVarBndrName (PlainTV  name)   = name
-tyVarBndrName (KindedTV name _) = name
-
 findTypeOrFail :: String -> Q Name
 findTypeOrFail s = lookupTypeName s >>= maybe (fail $ s ++ " is not in scope") return
 
@@ -86,7 +83,7 @@
 usesTV n (VarT name)  = n == name
 usesTV n (AppT t1 t2) = any (usesTV n) [t1, t2]
 usesTV n (SigT t  _ ) = usesTV n t
-usesTV n (ForallT bs _ t) = usesTV n t && n `notElem` map tyVarBndrName bs
+usesTV n (ForallT bs _ t) = usesTV n t && n `notElem` map tvName bs
 usesTV _ _ = False
 
 -- | Analyze constructor argument.
@@ -184,10 +181,7 @@
   , unlines (map (pprint . fst) xs) ]
 
 extractVars :: Type -> [Name]
-extractVars (ForallT bs _ t) = extractVars t \\ map bndrName bs
-  where
-    bndrName (PlainTV n) = n
-    bndrName (KindedTV n _) = n
+extractVars (ForallT bs _ t) = extractVars t \\ map tvName bs
 extractVars (VarT n) = [n]
 extractVars (AppT x y) = extractVars x ++ extractVars y
 #if MIN_VERSION_template_haskell(2,8,0)
@@ -202,7 +196,7 @@
 #endif
 extractVars _ = []
 
-liftCon' :: Bool -> [TyVarBndr] -> Cxt -> Type -> Type -> [Type] -> Name -> [Type] -> Q [Dec]
+liftCon' :: Bool -> [TyVarBndrSpec] -> Cxt -> Type -> Type -> [Type] -> Name -> [Type] -> Q [Dec]
 liftCon' typeSig tvbs cx f n ns cn ts = do
   -- prepare some names
   opName <- mkName <$> mkOpName (nameBase cn)
@@ -225,7 +219,7 @@
       exprs = zipExprs (map VarE xs) es args  -- this is what ctor would be applied to
       fval = foldl AppE (ConE cn) exprs       -- this is RHS without liftF
       ns' = nub (concatMap extractVars ns)
-      q = filter nonNext tvbs ++ map PlainTV (qa ++ m : ns')
+      q = filter nonNext tvbs ++ map plainTVSpecified (qa ++ m : ns')
       qa = case retType of VarT b | a == b -> [a]; _ -> []
       f' = foldl AppT f ns
   return $ concat
@@ -238,11 +232,10 @@
         else []
     , [ FunD opName [ Clause pat (NormalB $ AppE (VarE liftF) fval) [] ] ] ]
   where
-    nonNext (PlainTV pn) = VarT pn /= n
-    nonNext (KindedTV kn _) = VarT kn /= n
+    nonNext tv = VarT (tvName tv) /= n
 
 -- | Provide free monadic actions for a single value constructor.
-liftCon :: Bool -> [TyVarBndr] -> Cxt -> Type -> Type -> [Type] -> Maybe [Name] -> Con -> Q [Dec]
+liftCon :: Bool -> [TyVarBndrSpec] -> Cxt -> Type -> Type -> [Type] -> Maybe [Name] -> Con -> Q [Dec]
 liftCon typeSig ts cx f n ns onlyCons con
   | not (any (`melem` onlyCons) (constructorNames con)) = return []
   | otherwise = case con of
@@ -264,15 +257,21 @@
       _ -> fail $ "Unsupported constructor type: `" ++ pprint con ++ "'"
 
 #if MIN_VERSION_template_haskell(2,11,0)
-splitAppT :: Type -> [Type]
-splitAppT (AppT x y) = splitAppT x ++ [y]
-splitAppT t = [t]
+splitAppT :: Type -> (Type, [Type])
+splitAppT ty = go ty ty []
+  where
+    go :: Type -> Type -> [Type] -> (Type, [Type])
+    go _      (AppT ty1 ty2)     args = go ty1 ty1 (ty2:args)
+    go origTy (SigT ty' _)       args = go origTy ty' args
+    go origTy (InfixT ty1 n ty2) args = go origTy (ConT n `AppT` ty1 `AppT` ty2) args
+    go origTy (ParensT ty')      args = go origTy ty' args
+    go origTy _                  args = (origTy, args)
 
-liftGadtC :: Name -> [BangType] -> Type -> Bool -> [TyVarBndr] -> Cxt -> Type -> Q [Dec]
+liftGadtC :: Name -> [BangType] -> Type -> Bool -> [TyVarBndrSpec] -> Cxt -> Type -> Q [Dec]
 liftGadtC cName fields resType typeSig ts cx f =
   liftCon typeSig ts cx f nextTy (init tys) Nothing (NormalC cName fields)
   where
-    (_f : tys) = splitAppT resType
+    (_f, tys) = splitAppT resType
     nextTy = last tys
 #endif
 
@@ -305,7 +304,7 @@
   | null tyVarBndrs = fail $ "Type constructor " ++ pprint tyName ++ " needs at least one type parameter"
   | otherwise = concat <$> mapM (liftCon typeSig [] [] con nextTy (init tys) onlyCons) cons
     where
-      tys     = map (VarT . tyVarBndrName) tyVarBndrs
+      tys     = map (VarT . tvName) tyVarBndrs
       nextTy  = last tys
       con        = ConT tyName
 liftDec _ _ dec = fail $ unlines