diff --git a/.ghci b/.ghci
deleted file mode 100644
--- a/.ghci
+++ /dev/null
@@ -1,2 +0,0 @@
-:set -isrc -idist/build/autogen -optP-include -optPdist/build/autogen/cabal_macros.h -optP-Iincludes
-:set -v0
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
--- a/.travis.yml
+++ /dev/null
@@ -1,172 +0,0 @@
-# This Travis job script has been generated by a script via
-#
-#   haskell-ci '--output=.travis.yml' '--config=cabal.haskell-ci' 'cabal.project'
-#
-# For more information, see https://github.com/haskell-CI/haskell-ci
-#
-# version: 0.5.20180830
-#
-language: c
-dist: xenial
-git:
-  # whether to recursively clone submodules
-  submodules: false
-notifications:
-  irc:
-    channels:
-      - irc.freenode.org#haskell-lens
-    skip_join: true
-    template:
-      - "\"\\x0313bytes\\x03/\\x0306%{branch}\\x03 \\x0314%{commit}\\x03 %{build_url} %{message}\""
-cache:
-  directories:
-    - $HOME/.cabal/packages
-    - $HOME/.cabal/store
-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 $CABALHOME/packages/head.hackage
-matrix:
-  include:
-    - compiler: ghc-8.8.1
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.8.1","cabal-install-3.0"]}}
-    - compiler: ghc-8.6.5
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.6.5","cabal-install-3.0"]}}
-    - compiler: ghc-8.4.4
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.4.4","cabal-install-3.0"]}}
-    - compiler: ghc-8.2.2
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.2.2","cabal-install-3.0"]}}
-    - compiler: ghc-8.0.2
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.0.2","cabal-install-3.0"]}}
-    - compiler: ghc-7.10.3
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-7.10.3","cabal-install-3.0"]}}
-    - compiler: ghc-7.8.4
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-7.8.4","cabal-install-3.0"]}}
-    - compiler: ghc-7.6.3
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-7.6.3","cabal-install-3.0"]}}
-    - compiler: ghc-7.4.2
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-7.4.2","cabal-install-3.0"]}}
-    - compiler: ghc-head
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-head","cabal-install-head"]}}
-  allow_failures:
-    - compiler: ghc-head
-before_install:
-  - HC=$(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+markoutput"
-  - 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 -gt 80801 ] ; 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
-  - |
-    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
-  - 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
-  - |
-  - "for pkg in $($HCPKG list --simple-output); do echo $pkg | sed 's/-[^-]*$//' | (grep -vE -- '^(bytes)$' || true) | sed 's/^/constraints: /' | sed 's/$/ 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} | color_cabal_output
-  - "cat cabal.project.freeze | sed -E 's/^(constraints: *| *)//' | sed 's/any.//'"
-  - rm  cabal.project.freeze
-  - ${CABAL} v2-build $WITHCOMPILER ${TEST} ${BENCH} --dep -j2 all | color_cabal_output
-script:
-  - DISTDIR=$(mktemp -d /tmp/dist-test.XXXX)
-  # Packaging...
-  - ${CABAL} v2-sdist all | color_cabal_output
-  # Unpacking...
-  - mv dist-newstyle/sdist/*.tar.gz ${DISTDIR}/
-  - cd ${DISTDIR} || false
-  - find . -maxdepth 1 -type f -name '*.tar.gz' -exec tar -xvf '{}' \;
-  - find . -maxdepth 1 -type f -name '*.tar.gz' -exec rm       '{}' \;
-  - PKGDIR_bytes="$(find . -maxdepth 1 -type d -regex '.*/bytes-[0-9.]*')"
-  # Generate cabal.project
-  - rm -rf cabal.project cabal.project.local cabal.project.freeze
-  - touch cabal.project
-  - |
-    echo "packages: ${PKGDIR_bytes}" >> cabal.project
-  - |
-  - "for pkg in $($HCPKG list --simple-output); do echo $pkg | sed 's/-[^-]*$//' | (grep -vE -- '^(bytes)$' || true) | sed 's/^/constraints: /' | sed 's/$/ 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 | color_cabal_output
-  # Testing...
-  - ${CABAL} v2-test $WITHCOMPILER ${TEST} ${BENCH} all | color_cabal_output
-  # cabal check...
-  - (cd ${PKGDIR_bytes} && ${CABAL} -vnormal check)
-  # haddock...
-  - ${CABAL} v2-haddock $WITHCOMPILER --with-haddock $HADDOCK ${TEST} ${BENCH} all | color_cabal_output
-
-# REGENDATA ["--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 +1,12 @@
+0.17.1 [2021.02.17]
+-------------------
+* The build-type has been changed from `Custom` to `Simple`.
+  To achieve this, the `doctests` test suite has been removed in favor of using
+  [`cabal-docspec`](https://github.com/phadej/cabal-extras/tree/master/cabal-docspec)
+  to run the doctests.
+* Provide the `Serial Natural` instance unconditionally.
+* Allow building with `bytestring-0.11.*`.
+
 0.17 [2020.02.03]
 -----------------
 * Give `MonadGet m` a superclass of
diff --git a/README.markdown b/README.markdown
--- a/README.markdown
+++ b/README.markdown
@@ -1,7 +1,7 @@
 bytes
 =====
 
-[![Hackage](https://img.shields.io/hackage/v/bytes.svg)](https://hackage.haskell.org/package/bytes) [![Build Status](https://secure.travis-ci.org/ekmett/bytes.png?branch=master)](http://travis-ci.org/ekmett/bytes)
+[![Hackage](https://img.shields.io/hackage/v/bytes.svg)](https://hackage.haskell.org/package/bytes) [![Build Status](https://github.com/ekmett/bytes/workflows/Haskell-CI/badge.svg)](https://github.com/ekmett/bytes/actions?query=workflow%3AHaskell-CI)
 
 This package provides a simple compatibility shim that lets you work with both `binary` and `cereal` with one chunk of serialization code.
 
diff --git a/Setup.lhs b/Setup.lhs
--- a/Setup.lhs
+++ b/Setup.lhs
@@ -1,34 +1,7 @@
-\begin{code}
-{-# LANGUAGE CPP #-}
-{-# OPTIONS_GHC -Wall #-}
-module Main (main) where
-
-#ifndef MIN_VERSION_cabal_doctest
-#define MIN_VERSION_cabal_doctest(x,y,z) 0
-#endif
-
-#if MIN_VERSION_cabal_doctest(1,0,0)
-
-import Distribution.Extra.Doctest ( defaultMainWithDoctests )
-main :: IO ()
-main = defaultMainWithDoctests "doctests"
-
-#else
-
-#ifdef MIN_VERSION_Cabal
--- If the macro is defined, we have new cabal-install,
--- but for some reason we don't have cabal-doctest in package-db
---
--- Probably we are running cabal sdist, when otherwise using new-build
--- workflow
-import Warning ()
-#endif
-
-import Distribution.Simple
-
-main :: IO ()
-main = defaultMain
+#!/usr/bin/runhaskell
+> module Main (main) where
 
-#endif
+> import Distribution.Simple
 
-\end{code}
+> main :: IO ()
+> main = defaultMain
diff --git a/Warning.hs b/Warning.hs
deleted file mode 100644
--- a/Warning.hs
+++ /dev/null
@@ -1,5 +0,0 @@
-module Warning
-  {-# WARNING ["You are configuring this package without cabal-doctest installed.",
-               "The doctests test-suite will not work as a result.",
-               "To fix this, install cabal-doctest before configuring."] #-}
-  () where
diff --git a/bytes.cabal b/bytes.cabal
--- a/bytes.cabal
+++ b/bytes.cabal
@@ -1,8 +1,8 @@
 name:          bytes
 category:      Data, Serialization
-version:       0.17
+version:       0.17.1
 license:       BSD3
-cabal-version: >= 1.8
+cabal-version: >= 1.10
 license-file:  LICENSE
 author:        Edward A. Kmett
 maintainer:    Edward A. Kmett <ekmett@gmail.com>
@@ -10,7 +10,7 @@
 homepage:      https://github.com/ekmett/bytes
 bug-reports:   https://github.com/ekmett/bytes/issues
 copyright:     Copyright (C) 2013-2015 Edward A. Kmett
-build-type:    Custom
+build-type:    Simple
 tested-with:   GHC == 7.4.2
              , GHC == 7.6.3
              , GHC == 7.8.4
@@ -19,54 +19,35 @@
              , GHC == 8.2.2
              , GHC == 8.4.4
              , GHC == 8.6.5
-             , GHC == 8.8.1
+             , GHC == 8.8.4
+             , GHC == 8.10.3
 synopsis:      Sharing code for serialization between binary and cereal
 description:   Sharing code for serialization between binary and cereal.
 
 extra-source-files:
-  .travis.yml
-  .ghci
   .gitignore
   .hlint.yaml
   .vim.custom
-  travis/cabal-apt-install
-  travis/config
   AUTHORS.markdown
   README.markdown
   CHANGELOG.markdown
-  Warning.hs
 
 source-repository head
   type: git
   location: git://github.com/ekmett/bytes.git
 
--- You can disable the doctests test suite with -f-test-doctests
-flag test-doctests
-  description: Enable (or disable via f-test-doctests) the doctest suite when
-               using the enable-tests option for cabal.
-  default: True
-  manual: True
-
-custom-setup
-  -- any Cabal should do
-  setup-depends:
-    base          >= 4.5 && <5,
-    Cabal         >= 1.14,
-    cabal-doctest >= 1 && <1.1
-
-
 library
   build-depends:
     base                      >= 4.5      && < 5,
     binary                    >= 0.5.1    && < 0.9,
     binary-orphans            >= 1.0.1    && < 1.1,
-    bytestring                >= 0.9      && < 0.11,
+    bytestring                >= 0.9      && < 0.12,
     cereal                    >= 0.5.2    && < 0.6,
     containers                >= 0.3      && < 1,
     hashable                  >= 1.0.1.1  && < 1.4,
     mtl                       >= 2.0      && < 2.3,
     text                      >= 0.2      && < 1.3,
-    time                      >= 1.2      && < 1.10,
+    time                      >= 1.2      && < 1.11,
     transformers              >= 0.2      && < 0.6,
     transformers-compat       >= 0.6.5    && < 1,
     unordered-containers      >= 0.2      && < 0.3,
@@ -76,6 +57,9 @@
   if impl(ghc >= 7.4 && < 7.6)
     build-depends: ghc-prim
 
+  if !impl(ghc >= 7.10)
+    build-depends: nats >= 1.1.2   && < 1.2
+
   if !impl(ghc >= 8.0)
     build-depends: semigroups >= 0.5      && < 1
                  , fail       >= 4.9.0.0  && < 4.10
@@ -88,21 +72,8 @@
     Data.Bytes.VarInt
 
   ghc-options: -Wall -fwarn-tabs -O2
+  if impl(ghc >= 8.6)
+    ghc-options: -Wno-star-is-type
   c-sources: cbits/i2d.c
   hs-source-dirs: src
-
-test-suite doctests
-  type:           exitcode-stdio-1.0
-  main-is:        doctests.hs
-  ghc-options:    -Wall -threaded
-  hs-source-dirs: tests
-
-  if !flag(test-doctests)
-    buildable: False
-  else
-    build-depends:
-      base,
-      bytes,
-      directory      >= 1.0,
-      doctest        >= 0.11.1 && <0.17,
-      filepath       >= 1.2
+  default-language: Haskell2010
diff --git a/src/Data/Bytes/Serial.hs b/src/Data/Bytes/Serial.hs
--- a/src/Data/Bytes/Serial.hs
+++ b/src/Data/Bytes/Serial.hs
@@ -98,16 +98,25 @@
 import GHC.Exts (Down(..))
 import GHC.Generics
 import System.IO.Unsafe
-
-#if MIN_VERSION_base(4,8,0)
 import Numeric.Natural
-#endif
 
 foreign import ccall floatToWord32 :: Float -> Word32
 foreign import ccall word32ToFloat :: Word32 -> Float
 foreign import ccall doubleToWord64 :: Double -> Word64
 foreign import ccall word64ToDouble :: Word64 -> Double
 
+-- $setup
+-- >>> import Data.Bytes.Get
+-- >>> import Data.Bytes.Put
+-- >>> import Data.Bytes.VarInt
+-- >>> import Data.Fixed
+-- >>> import Data.Ratio (Ratio, (%))
+-- >>> import Data.Time
+-- >>> import Data.Time.Clock
+-- >>> import Data.Time.Clock.TAI
+-- >>> import Data.Word
+-- >>> import Numeric.Natural
+
 ------------------------------------------------------------------------------
 -- Endianness-Dependant Serialization
 ------------------------------------------------------------------------------
@@ -279,7 +288,13 @@
 restore :: forall m a. (MonadGet m, Storable a) => m a
 restore = do
   let required = sizeOf (undefined :: a)
-  PS fp o n <- getByteString required
+#if MIN_VERSION_bytestring(0,11,0)
+  let o = 0
+  BS fp n
+#else
+  PS fp o n
+#endif
+    <- getByteString required
   unless (n >= required) $ MonadFail.fail "restore: Required more bytes"
   return $ unsafePerformIO $ withForeignPtr fp $ \p -> peekByteOff p o
 
@@ -393,11 +408,6 @@
   | otherwise = return $ fromIntegral n
 {-# INLINE getVarInt #-}
 
--- |
--- $setup
--- >>> import Data.Word
--- >>> import Data.Fixed
--- >>> import Data.Bytes.Serial
 
 -- | Integer/Word types serialized to base-128 variable-width ints.
 --
@@ -420,14 +430,12 @@
   serialize = serialize . VarInt
   deserialize = unVarInt `liftM` deserialize
 
-#if MIN_VERSION_base(4,8,0)
 -- |
 -- >>> runGetL deserialize (runPutL (serialize (10^10::Natural))) :: Natural
 -- 10000000000
 instance Serial Natural where
   serialize = serialize . VarInt . toInteger
   deserialize = fromInteger . unVarInt <$> deserialize
-#endif
 
 -- |
 -- >>> (runGetL deserialize $ runPutL $ serialize (1.82::Fixed E2))::Fixed E2
diff --git a/tests/doctests.hs b/tests/doctests.hs
deleted file mode 100644
--- a/tests/doctests.hs
+++ /dev/null
@@ -1,25 +0,0 @@
------------------------------------------------------------------------------
--- |
--- Module      :  Main (doctests)
--- Copyright   :  (C) 2012-14 Edward Kmett
--- License     :  BSD-style (see the file LICENSE)
--- Maintainer  :  Edward Kmett <ekmett@gmail.com>
--- Stability   :  provisional
--- Portability :  portable
---
--- This module provides doctests for a project based on the actual versions
--- of the packages it was built with. It requires a corresponding Setup.lhs
--- to be added to the project
------------------------------------------------------------------------------
-module Main where
-
-import Build_doctests (flags, pkgs, module_sources)
-import Data.Foldable (traverse_)
-import Test.DocTest
-
-main :: IO ()
-main = do
-    traverse_ putStrLn args
-    doctest args
-  where
-    args = flags ++ pkgs ++ module_sources
diff --git a/travis/cabal-apt-install b/travis/cabal-apt-install
deleted file mode 100644
--- a/travis/cabal-apt-install
+++ /dev/null
@@ -1,27 +0,0 @@
-#! /bin/bash
-set -eu
-
-APT="sudo apt-get -q -y"
-CABAL_INSTALL_DEPS="cabal install --only-dependencies --force-reinstall"
-
-$APT update
-$APT install dctrl-tools
-
-# Find potential system packages to satisfy cabal dependencies
-deps()
-{
-	local M='^\([^ ]\+\)-[0-9.]\+ (.*$'
-	local G=' -o ( -FPackage -X libghc-\L\1\E-dev )'
-	local E="$($CABAL_INSTALL_DEPS "$@" --dry-run -v 2> /dev/null \
-		| sed -ne "s/$M/$G/p" | sort -u)"
-	grep-aptavail -n -sPackage \( -FNone -X None \) $E | sort -u
-}
-
-$APT install $(deps "$@") libghc-quickcheck2-dev # QuickCheck is special
-$CABAL_INSTALL_DEPS "$@" # Install the rest via Hackage
-
-if ! $APT install hlint ; then
-	$APT install $(deps hlint)
-	cabal install hlint
-fi
-
diff --git a/travis/config b/travis/config
deleted file mode 100644
--- a/travis/config
+++ /dev/null
@@ -1,16 +0,0 @@
--- This provides a custom ~/.cabal/config file for use when hackage is down that should work on unix
---
--- This is particularly useful for travis-ci to get it to stop complaining
--- about a broken build when everything is still correct on our end.
---
--- This uses Luite Stegeman's mirror of hackage provided by his 'hdiff' site instead
---
--- To enable this, uncomment the before_script in .travis.yml
-
-remote-repo: hdiff.luite.com:http://hdiff.luite.com/packages/archive
-remote-repo-cache: ~/.cabal/packages
-world-file: ~/.cabal/world
-build-summary: ~/.cabal/logs/build.log
-remote-build-reporting: anonymous
-install-dirs user
-install-dirs global