diff --git a/CREDITS b/CREDITS
index 5dd8821ff73..5f1285a031f 100644
--- a/CREDITS
+++ b/CREDITS
@@ -1,5 +1,5 @@
 {{int:version-credits-summary}} <!--
-MediaWiki 1.41 is a collaborative project released under the
+MediaWiki 1.42 is a collaborative project released under the
 GNU General Public License v2. We would like to recognize the
 following names for their contribution to the product.
 
diff --git a/HISTORY b/HISTORY
index 0e3322a038a..fa4985383ca 100644
--- a/HISTORY
+++ b/HISTORY
@@ -1,4 +1,4 @@
-Change notes from older releases. For current info, see RELEASE-NOTES-1.41.
+Change notes from older releases. For current info, see RELEASE-NOTES-1.42.
 
 = MediaWiki 1.40 =
 
diff --git a/INSTALL b/INSTALL
index 04daef65bfe..1d4c8865dae 100644
--- a/INSTALL
+++ b/INSTALL
@@ -5,7 +5,7 @@ Installing MediaWiki
 Starting with MediaWiki 1.2.0, it's possible to install and configure the wiki
 "in-place", as long as you have the necessary prerequisites available.
 
-Required software as of MediaWiki 1.41.0:
+Required software as of MediaWiki 1.42.0:
 
 * Web server with PHP 7.4.3 or higher, plus the following extensions:
 ** ctype
diff --git a/RELEASE-NOTES-1.42 b/RELEASE-NOTES-1.42
new file mode 100644
index 00000000000..d61ee888520
--- /dev/null
+++ b/RELEASE-NOTES-1.42
@@ -0,0 +1,127 @@
+= MediaWiki 1.42 =
+
+== MediaWiki 1.42.0-PRERELEASE ==
+
+THIS IS NOT A RELEASE YET
+
+MediaWiki 1.42 is an alpha-quality development branch, and is not recommended
+for use in production.
+
+== Upgrading notes for 1.42 ==
+Don't forget to always back up your database before upgrading!
+
+See the file UPGRADE for more detailed per-version upgrade instructions from the
+oldest supported upgrading version, MediaWiki 1.35.
+
+Some specific notes for MediaWiki 1.42 upgrades are below:
+* …
+
+For notes on 1.41.x and older releases, see HISTORY.
+
+=== Configuration changes for system administrators in 1.42 ===
+* …
+
+==== New configuration ====
+* …
+
+==== Changed configuration ====
+* …
+
+==== Removed configuration ====
+* …
+
+=== New user-facing features in 1.42 ===
+* …
+
+=== New features for sysadmins in 1.42 ===
+* …
+
+=== New developer features in 1.42 ===
+* …
+
+=== External library changes in 1.42 ===
+
+==== New external libraries ====
+* …
+
+===== New development-only external libraries =====
+* …
+
+==== Changed external libraries ====
+* …
+
+===== Changed development-only external libraries =====
+* …
+
+==== Removed external libraries ====
+* …
+
+=== Bug fixes in 1.42 ===
+* …
+
+=== Action API changes in 1.42 ===
+* …
+
+=== Action API internal changes in 1.42 ===
+* …
+
+=== Languages updated in 1.42 ===
+MediaWiki supports over 350 languages. Many localisations are updated regularly.
+Below only new and removed languages are listed, as well as changes to languages
+because of Phabricator reports.
+
+* …
+
+=== Breaking changes in 1.42 ===
+* …
+
+=== Deprecations in 1.42 ===
+* …
+
+=== Other changes in 1.42 ===
+* …
+
+== Compatibility ==
+
+MediaWiki 1.42 requires PHP 7.4.3 or later and the following PHP extensions:
+
+* ctype
+* dom
+* fileinfo
+* iconv
+* intl
+* json
+* mbstring
+* xml
+
+MariaDB is the recommended database software. MySQL, PostgreSQL, or SQLite can
+be used instead, but support for them is somewhat less mature.
+
+The supported versions are:
+
+* MariaDB 10.3 or higher
+* MySQL 5.7.0 or higher
+* PostgreSQL 10 or later
+* SQLite 3.8.0 or later
+
+== Online documentation ==
+Documentation for both end-users and site administrators is available on
+MediaWiki.org, and is covered under the GNU Free Documentation License (except
+for pages that explicitly state that their contents are in the public domain):
+
+       https://www.mediawiki.org/wiki/Special:MyLanguage/Documentation
+
+== Mailing list ==
+A mailing list is available for MediaWiki user support and discussion:
+
+       https://lists.wikimedia.org/mailman/listinfo/mediawiki-l
+
+A low-traffic announcements-only list is also available:
+
+       https://lists.wikimedia.org/mailman/listinfo/mediawiki-announce
+
+It's highly recommended that you sign up for one of these lists if you're
+going to run a public MediaWiki, so you can be notified of security fixes.
+
+== IRC help ==
+There's usually someone online in #mediawiki on irc.libera.chat.
diff --git a/includes/Defines.php b/includes/Defines.php
index 72d297edac4..dd3755c76ab 100644
--- a/includes/Defines.php
+++ b/includes/Defines.php
@@ -33,7 +33,7 @@ use Wikimedia\Rdbms\IDatabase;
  *
  * @since 1.35 (also backported to 1.33.3 and 1.34.1)
  */
-define( 'MW_VERSION', '1.41.0-alpha' );
+define( 'MW_VERSION', '1.42.0-alpha' );
 
 /** @{
  * Obsolete IDatabase::makeList() constants
diff --git a/includes/PHPVersionCheck.php b/includes/PHPVersionCheck.php
index cf146a9a764..3940a88f75a 100644
--- a/includes/PHPVersionCheck.php
+++ b/includes/PHPVersionCheck.php
@@ -33,7 +33,7 @@
  */
 class PHPVersionCheck {
 	/** @var string The number of the MediaWiki version used. If you're updating MW_VERSION in Defines.php, you must also update this value. */
-	var $mwVersion = '1.41';
+	var $mwVersion = '1.42';
 
 	/** @var string[] A mapping of PHP functions to PHP extensions. */
 	var $functionsExtensionsMapping = array(