diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
--- a/.travis.yml
+++ /dev/null
@@ -1,173 +0,0 @@
-# This Travis job script has been generated by a script via
-#
-#   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: 0.10
-#
-version: ~> 1.0
-language: c
-os: linux
-dist: xenial
-git:
-  # whether to recursively clone submodules
-  submodules: false
-notifications:
-  irc:
-    channels:
-      - irc.freenode.org#haskell-lens
-    skip_join: true
-    template:
-      - "\x0313bifunctors\x03/\x0306%{branch}\x03 \x0314%{commit}\x03 %{build_url} %{message}"
-cache:
-  directories:
-    - $HOME/.cabal/packages
-    - $HOME/.cabal/store
-    - $HOME/.hlint
-before_cache:
-  - rm -fv $CABALHOME/packages/hackage.haskell.org/build-reports.log
-  # remove files that are regenerated by 'cabal update'
-  - 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 $CABALHOME/packages/head.hackage
-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-3.2"]}}
-      os: linux
-    - 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-3.2"]}}
-      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-3.2"]}}
-      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-3.2"]}}
-      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-3.2"]}}
-      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-3.2"]}}
-      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-3.2"]}}
-      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-3.2"]}}
-      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-3.2"]}}
-      os: linux
-    - compiler: ghc-7.2.2
-      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-7.2.2","cabal-install-3.2"]}}
-      os: linux
-    - compiler: ghc-7.0.4
-      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-7.0.4","cabal-install-3.2"]}}
-      os: linux
-  allow_failures:
-    - compiler: ghc-7.0.4
-    - compiler: ghc-7.2.2
-before_install:
-  - HC=$(echo "/opt/$CC/bin/ghc" | sed 's/-/\//')
-  - WITHCOMPILER="-w $HC"
-  - HADDOCK=$(echo "/opt/$CC/bin/haddock" | sed 's/-/\//')
-  - HCPKG="$HC-pkg"
-  - unset CC
-  - CABAL=/opt/ghc/bin/cabal
-  - CABALHOME=$HOME/.cabal
-  - export PATH="$CABALHOME/bin:$PATH"
-  - TOP=$(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"
-  - set -o pipefail
-  - TEST=--enable-tests
-  - BENCH=--enable-benchmarks
-  - HEADHACKAGE=false
-  - 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
-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
-  - cat $CABALHOME/config
-  - rm -fv cabal.project cabal.project.local cabal.project.freeze
-  - travis_retry ${CABAL} v2-update -v
-  # Generate cabal.project
-  - rm -rf cabal.project cabal.project.local cabal.project.freeze
-  - touch cabal.project
-  - |
-    echo "packages: ." >> cabal.project
-  - if [ $HCNUMVER -ge 80200 ] ; then echo 'package bifunctors' >> cabal.project ; fi
-  - "if [ $HCNUMVER -ge 80200 ] ; then echo '  ghc-options: -Werror=missing-methods' >> cabal.project ; fi"
-  - |
-  - "for pkg in $($HCPKG list --simple-output); do echo $pkg | sed 's/-[^-]*$//' | (grep -vE -- '^(bifunctors)$' || true) | sed 's/^/constraints: /' | sed 's/$/ installed/' >> cabal.project.local; done"
-  - cat cabal.project || true
-  - cat cabal.project.local || true
-  - if [ -f "./configure.ac" ]; then (cd "." && autoreconf -i); fi
-  - ${CABAL} v2-freeze $WITHCOMPILER ${TEST} ${BENCH}
-  - "cat cabal.project.freeze | sed -E 's/^(constraints: *| *)//' | sed 's/any.//'"
-  - rm  cabal.project.freeze
-  - 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
-  # Unpacking...
-  - mv dist-newstyle/sdist/*.tar.gz ${DISTDIR}/
-  - cd ${DISTDIR} || false
-  - find . -maxdepth 1 -type f -name '*.tar.gz' -exec tar -xvf '{}' \;
-  - find . -maxdepth 1 -type f -name '*.tar.gz' -exec rm       '{}' \;
-  - PKGDIR_bifunctors="$(find . -maxdepth 1 -type d -regex '.*/bifunctors-[0-9.]*')"
-  # Generate cabal.project
-  - rm -rf cabal.project cabal.project.local cabal.project.freeze
-  - touch cabal.project
-  - |
-    echo "packages: ${PKGDIR_bifunctors}" >> cabal.project
-  - if [ $HCNUMVER -ge 80200 ] ; then echo 'package bifunctors' >> cabal.project ; fi
-  - "if [ $HCNUMVER -ge 80200 ] ; then echo '  ghc-options: -Werror=missing-methods' >> cabal.project ; fi"
-  - |
-  - "for pkg in $($HCPKG list --simple-output); do echo $pkg | sed 's/-[^-]*$//' | (grep -vE -- '^(bifunctors)$' || true) | sed 's/^/constraints: /' | sed 's/$/ installed/' >> cabal.project.local; done"
-  - cat cabal.project || true
-  - cat cabal.project.local || true
-  # Building with tests and benchmarks...
-  # build & run tests, build benchmarks
-  - ${CABAL} v2-build $WITHCOMPILER ${TEST} ${BENCH} all
-  # Testing...
-  - ${CABAL} v2-test $WITHCOMPILER ${TEST} ${BENCH} all
-  # cabal check...
-  - (cd ${PKGDIR_bifunctors} && ${CABAL} -vnormal check)
-  # haddock...
-  - ${CABAL} v2-haddock $WITHCOMPILER --with-haddock $HADDOCK ${TEST} ${BENCH} all
-
-# 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 @@
+5.5.9 [2020.12.30]
+------------------
+* Explicitly mark modules as Safe or Trustworthy.
+
 5.5.8 [2020.10.01]
 ------------------
 * Fix a bug in which `deriveBifunctor` would fail on sufficiently complex uses
diff --git a/README.markdown b/README.markdown
--- a/README.markdown
+++ b/README.markdown
@@ -1,7 +1,7 @@
 bifunctors
 ==========
 
-[![Hackage](https://img.shields.io/hackage/v/bifunctors.svg)](https://hackage.haskell.org/package/bifunctors) [![Build Status](https://secure.travis-ci.org/ekmett/bifunctors.png?branch=master)](http://travis-ci.org/ekmett/bifunctors)
+[![Hackage](https://img.shields.io/hackage/v/bifunctors.svg)](https://hackage.haskell.org/package/bifunctors) [![Build Status](https://github.com/ekmett/bifunctors/workflows/Haskell-CI/badge.svg)](https://github.com/ekmett/bifunctors/actions?query=workflow%3AHaskell-CI)
 
 Contact Information
 -------------------
diff --git a/bifunctors.cabal b/bifunctors.cabal
--- a/bifunctors.cabal
+++ b/bifunctors.cabal
@@ -1,6 +1,6 @@
 name:          bifunctors
 category:      Data, Functors
-version:       5.5.8
+version:       5.5.9
 license:       BSD3
 cabal-version: >= 1.10
 license-file:  LICENSE
@@ -26,7 +26,6 @@
              , GHC == 8.8.3
              , GHC == 8.10.1
 extra-source-files:
-  .travis.yml
   CHANGELOG.markdown
   README.markdown
   include/bifunctors-common.h
@@ -56,13 +55,13 @@
   include-dirs: include
   includes: bifunctors-common.h
   build-depends:
-    base                >= 4     && < 5,
-    base-orphans        >= 0.5.2 && < 1,
-    comonad             >= 4     && < 6,
-    containers          >= 0.1   && < 0.7,
+    base                >= 4.3   && < 5,
+    base-orphans        >= 0.8.4 && < 1,
+    comonad             >= 5.0.7 && < 6,
+    containers          >= 0.2   && < 0.7,
     template-haskell    >= 2.4   && < 2.18,
-    th-abstraction      >= 0.4   && < 0.5,
-    transformers        >= 0.2   && < 0.6
+    th-abstraction      >= 0.4.2.0 && < 0.5,
+    transformers        >= 0.3   && < 0.6
 
   if !impl(ghc > 8.2)
     build-depends: transformers-compat >= 0.5 && < 0.7
@@ -71,10 +70,10 @@
     build-depends: fail == 4.9.*
 
   if flag(tagged)
-    build-depends: tagged >= 0.7.3 && < 1
+    build-depends: tagged >= 0.8.6 && < 1
 
   if flag(semigroups) && !impl(ghc >= 8.0)
-    build-depends: semigroups >= 0.16.2 && < 1
+    build-depends: semigroups >= 0.18.5 && < 1
 
   if impl(ghc<7.9)
     hs-source-dirs: old-src/ghc709
@@ -112,6 +111,10 @@
   ghc-options: -Wall
   default-language: Haskell2010
 
+  if impl(ghc >= 9.0)
+    -- these flags may abort compilation with GHC-8.10
+    -- https://gitlab.haskell.org/ghc/ghc/-/merge_requests/3295
+    ghc-options: -Winferred-safe-imports -Wmissing-safe-haskell-mode
 
 test-suite bifunctors-spec
   type: exitcode-stdio-1.0
diff --git a/src/Data/Bifunctor/Biap.hs b/src/Data/Bifunctor/Biap.hs
--- a/src/Data/Bifunctor/Biap.hs
+++ b/src/Data/Bifunctor/Biap.hs
@@ -10,6 +10,10 @@
 {-# LANGUAGE DeriveGeneric              #-}
 #endif
 
+-- This module uses GND
+#if __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
 #include "bifunctors-common.h"
 
 -----------------------------------------------------------------------------