diff --git a/CHANGELOG.md b/CHANGELOG.md
index 63f004f..129da0c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,13 +2,26 @@
 
 ## pre-v4.0.0
 
+ * Fix unexpected crash during SSL tests:
+   https://github.com/elli-lib/elli/pull/91
+
+ * Do not spawn a new acceptor until after a successful TLS handhake:
+   https://github.com/elli-lib/elli/pull/90
+
  * Headers are now properly treated as case-insensitive
- * Original headers that have not had `string:casefold/1` run on each header
- name are still available in the request through `elli_request:original_headers`
+   Original headers that have not had `string:casefold/1` run on each header
+   name are still available in the request through `elli_request:original_headers`:
+   https://github.com/elli-lib/elli/pull/92
+
+ * Handle uncommon integer status codes (as per `elli:response_code/0`):
+   https://github.com/elli-lib/elli/pull/96
+
+  * In `elli_http` export `send_file/5` and `close_or_keepalive/2`:
+    https://github.com/elli-lib/elli/pull/98
 
 ## v3.3.0
 
- * Do not use x-forwarded-for for peer #75 
+ * Do not use x-forwarded-for for peer #75
  * Handle arguments with no value in (post|get)_arg_decoded #82
  * Fix compile-time warnings on missing record info. from aleppo #81
 
diff --git a/LICENSE b/LICENSE
index 40b68e0..c00c84a 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,7 +1,7 @@
 The MIT License
 
 Copyright (c) 2012-2016 Knut Nesheim
-Copyright (c) 2016-2018 elli-lib team
+Copyright (c) 2016-2021 elli-lib team
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/README.md b/README.md
index 32ffe90..b7b406a 100644
--- a/README.md
+++ b/README.md
@@ -14,8 +14,8 @@
 [erlang downloads]: http://www.erlang.org/downloads
 [doc badge]: https://img.shields.io/badge/docs-edown-green.svg
 [docs]: doc/README.md
-[coveralls badge]: https://coveralls.io/repos/github/elli-lib/elli/badge.svg?branch=develop
-[coveralls link]: https://coveralls.io/github/elli-lib/elli?branch=develop
+[coveralls badge]: https://coveralls.io/repos/github/elli-lib/elli/badge.svg?branch=main
+[coveralls link]: https://coveralls.io/github/elli-lib/elli?branch=main
 [license badge]: https://img.shields.io/badge/license-MIT-blue.svg
 
 Elli is a webserver you can run inside your Erlang application to
@@ -27,7 +27,7 @@ webserver, `elli` might be for you. If you're building web services,
 not web sites, then `elli` might be for you.
 
 Elli is used in production at Wooga and Game Analytics. Elli requires
-OTP 18.0 or newer.
+OTP 20.0 or newer.
 
 
 ## Installation
@@ -40,7 +40,7 @@ Add `elli` to your application by adding it as a dependency to your
 ```erlang
 {deps, [
   %% ...
-  {elli, "3.0.0"}
+  {elli, "4.0.0"}
 ]}.
 ```
 
diff --git a/doc/.editorconfig b/doc/.editorconfig
new file mode 100644
index 0000000..4ee5664
--- /dev/null
+++ b/doc/.editorconfig
@@ -0,0 +1,10 @@
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 4
+indent_style = space
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[Makefile]
+indent_style = tab
diff --git a/doc/Makefile b/doc/Makefile
index 5d72b03..da351af 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -3,9 +3,9 @@ SOURCE_DOCS := $(wildcard *.md)
 EXPORTED_DOCS=\
  $(SOURCE_DOCS:.md=.html)
 
-RM=/bin/rm
+RM ?= /bin/rm -f
 
-PANDOC=pandoc
+PANDOC ?= pandoc
 
 PANDOC_HTML_OPTIONS=--standalone --highlight-style=tango --template tpl.html -f gfm --to html5
 
@@ -18,4 +18,4 @@ PANDOC_HTML_OPTIONS=--standalone --highlight-style=tango --template tpl.html -f
 all : $(EXPORTED_DOCS)
 
 clean:
-	- $(RM) -f $(EXPORTED_DOCS)
+	- $(RM) $(EXPORTED_DOCS)
diff --git a/doc/README.md b/doc/README.md
index f206730..4466973 100644
--- a/doc/README.md
+++ b/doc/README.md
@@ -2,9 +2,9 @@
 
 # elli #
 
-Copyright (c) 2012-2016 Knut Nesheim, 2016-2018 elli-lib team
+Copyright (c) 2012-2016 Knut Nesheim, 2016-2021 elli-lib team
 
-__Version:__ 3.0.0
+__Version:__ 4.0.0
 
 __Authors:__ Knut Nesheim, elli-lib team.
 
diff --git a/doc/build.sh b/doc/build.sh
index 188a5ee..2a9094e 100755
--- a/doc/build.sh
+++ b/doc/build.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#! /usr/bin/env bash
 
 cd $(dirname $(realpath $0))
 
@@ -7,7 +7,7 @@ make
 
 # fix internal doc links
 sed -i 's/https:\/\/github\.com\/doc\/\([a-zA-Z_-]*\)\.md/\1.html/g' *.html
-sed -i 's/\"\([a-zA-Z_-]*\)\.md\([a-zA-Z_-#]*\)\"/\"\1.html\2\"/g' *.html
+sed -i 's/\"\([a-zA-Z_-]*\)\.md\([a-zA-Z#_-]*\)\"/\"\1.html\2\"/g' *.html
 sed -i 's/\"doc\/\([a-zA-Z_-]*\)\.md\"/\"\1.html\"/g' *.html
 sed -i 's/\"\([a-zA-Z_-]*\)\.md\"/\"\1.html\"/g' *.html
 
diff --git a/doc/index.md b/doc/index.md
index 2f1d9e6..6011fb7 100644
--- a/doc/index.md
+++ b/doc/index.md
@@ -3,25 +3,23 @@
 [![Hex.pm][hex badge]][hex package]
 [![Documentation][doc badge]][docs]
 [![Erlang][erlang badge]][erlang downloads]
-[![Travis CI][travis badge]][travis builds]
+![Common Test](https://github.com/elli-lib/elli/workflows/Common%20Test/badge.svg)
 [![Coverage Status][coveralls badge]][coveralls link]
 [![MIT License][license badge]](LICENSE)
 
-[travis builds]: https://travis-ci.org/elli-lib/elli
-[travis badge]: https://travis-ci.org/elli-lib/elli.svg
 [hex badge]: https://img.shields.io/hexpm/v/elli.svg
 [hex package]: https://hex.pm/packages/elli
 [latest release]: https://github.com/elli-lib/elli/releases/latest
-[erlang badge]: https://img.shields.io/badge/erlang-%E2%89%A518.0-red.svg
+[erlang badge]: https://img.shields.io/badge/erlang-%E2%89%A520.0-red.svg
 [erlang downloads]: http://www.erlang.org/downloads
 [doc badge]: https://img.shields.io/badge/docs-edown-green.svg
 [docs]: doc/README.md
-[coveralls badge]: https://coveralls.io/repos/github/elli-lib/elli/badge.svg?branch=develop
-[coveralls link]: https://coveralls.io/github/elli-lib/elli?branch=develop
+[coveralls badge]: https://coveralls.io/repos/github/elli-lib/elli/badge.svg?branch=main
+[coveralls link]: https://coveralls.io/github/elli-lib/elli?branch=main
 [license badge]: https://img.shields.io/badge/license-MIT-blue.svg
 
 Elli is a webserver you can run inside your Erlang application to
-expose an HTTP API. Elli is a aimed exclusively at building
+expose an HTTP API. Elli is aimed exclusively at building
 high-throughput, low-latency HTTP APIs. If robustness and performance
 is more important than general purpose features, then `elli` might be
 for you. If you find yourself digging into the implementation of a
@@ -29,7 +27,7 @@ webserver, `elli` might be for you. If you're building web services,
 not web sites, then `elli` might be for you.
 
 Elli is used in production at Wooga and Game Analytics. Elli requires
-OTP 18.0 or newer.
+OTP 20.0 or newer.
 
 
 ## Installation
@@ -40,7 +38,10 @@ Add `elli` to your application by adding it as a dependency to your
 [`rebar.config`](http://www.rebar3.org/docs/configuration):
 
 ```erlang
-{deps, [elli]}.
+{deps, [
+  %% ...
+  {elli, "4.0.0"}
+]}.
 ```
 
 Afterwards you can run:
@@ -302,4 +303,4 @@ about benchmarking HTTP servers.
 
 Elli is licensed under [The MIT License](LICENSE).
 
-Copyright (c) 2012-2016 Knut Nesheim, 2016-2018 elli-lib team
+Copyright (c) 2012-2016 Knut Nesheim, 2016-2021 elli-lib team
diff --git a/doc/overview.edoc b/doc/overview.edoc
index be8cd8c..461ecfa 100644
--- a/doc/overview.edoc
+++ b/doc/overview.edoc
@@ -1,7 +1,7 @@
 @author Knut Nesheim
 @author elli-lib team
-@copyright 2012-2016 Knut Nesheim, 2016-2018 elli-lib team
-@version 3.0.0
+@copyright 2012-2016 Knut Nesheim, 2016-2021 elli-lib team
+@version 4.0.0
 @title elli
 @doc Erlang web server for HTTP APIs
 
diff --git a/src/elli.app.src b/src/elli.app.src
index f3dee87..5c8cd4e 100644
--- a/src/elli.app.src
+++ b/src/elli.app.src
@@ -1,7 +1,7 @@
 {application, elli,
  [
   {description, "Erlang web server for HTTP APIs"},
-  {vsn, "3.3.0"},
+  {vsn, "4.0.0"},
   {modules, [
              elli,
              elli_example_callback,