diff --git a/.VERSION b/.VERSION
index 26d99a283..03f488b07 100644
--- a/.VERSION
+++ b/.VERSION
@@ -1 +1 @@
-5.2.1
+5.3.0
diff --git a/.mailmap b/.mailmap
index 9b4e92f95..0091f1120 100644
--- a/.mailmap
+++ b/.mailmap
@@ -23,6 +23,7 @@ James Mitchell <jdm3@st-andrews.ac.uk> James Mitchell <james-d-mitchell@users.no
 James Mitchell <jdm3@st-andrews.ac.uk> james-d-mitchell <james-d-mitchell@users.noreply.github.com>
 James Mitchell <jdm3@st-andrews.ac.uk> jamesm <unknown>
 Dima Pasechnik <dmitrii.pasechnik@cs.ox.ac.uk> Dima Pasechnik <dimpase@gmail.com>
+Dima Pasechnik <dmitrii.pasechnik@cs.ox.ac.uk> Dima Pasechnik <dima@pasechnik.info>
 Markus Pfeiffer <markus.pfeiffer@morphism.de> Markus Pfeiffer <markus.pfeiffer@st-andrews.ac.uk>
 Markus Pfeiffer <markus.pfeiffer@morphism.de> Markus Pfeiffer <markusp@mcs.st-andrews.ac.uk>
 Chris Russell <cr66@st-andrews.ac.uk> ChristopherRussell <cr66@st-andrews.ac.uk>
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8f1f4f617..cfa9930a3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,54 @@ Copyright © 2011-2023 [James D. Mitchell][] et al.
 
 Licensing information can be found in the `LICENSE` file.
 
+### Version 5.3.0 (released 18/09/2023)
+
+This release contains a fairly large number of changes, fixes, and
+improvements. The biggest changes/new features in this release are:
+
+* The build system has been completely updated by @fingolfin and @dimapase:
+  - Convert buildsystem to use Makefile.gappkg instead of automake by @fingolfin
+    in https://github.com/semigroups/Semigroups/pull/902
+  - Use the C++ compiler to link semigroups.so by @fingolfin in
+    https://github.com/semigroups/Semigroups/pull/942
+  - Work around autoconf 2.69 bugs by @fingolfin in
+    https://github.com/semigroups/Semigroups/pull/947
+  - set rpath for external libsemigroups by @dimpase in
+    https://github.com/semigroups/Semigroups/pull/954
+  - buildsystem: sane warning if not using gmake by @james-d-mitchell in
+    https://github.com/semigroups/Semigroups/pull/955
+* Some updates to improve the performance of `LatticeOfCongruences` and friends
+  by @james-d-mitchell in https://github.com/semigroups/Semigroups/pull/884
+* Add `GreensLeftMultipliers` and related by @james-d-mitchell in
+  https://github.com/semigroups/Semigroups/pull/925
+
+The following bugs were fixed and/or issues resolved:
+
+* Use same URL as in my other packages by @olexandr-konovalov in
+  https://github.com/semigroups/Semigroups/pull/907
+* Fix a few typos inn the doc by @fingolfin in
+  https://github.com/semigroups/Semigroups/pull/913
+* Increase required version of Digraphs and remove some redundant code by
+  @james-d-mitchell in https://github.com/semigroups/Semigroups/pull/921
+* greens: fix `HClassReps(LClass)` for acting semigroups by @james-d-mitchell
+  in https://github.com/semigroups/Semigroups/pull/927
+* greens: fix bug in `RightGreensMultiplier` for acting semigroups by
+  @james-d-mitchell in https://github.com/semigroups/Semigroups/pull/930
+* congsemigraph: add `\=` method by @james-d-mitchell in
+  https://github.com/semigroups/Semigroups/pull/933
+* greens: fix `RhoOrbStabChain(DClass)` by @james-d-mitchell in
+  https://github.com/semigroups/Semigroups/pull/932
+* doc: remove empty xml files by @james-d-mitchell in
+  https://github.com/semigroups/Semigroups/pull/934
+* Fix a typo that breaks HPCombi support by @fingolfin in
+  https://github.com/semigroups/Semigroups/pull/941
+* typo (ERNEL<-KERNEL) in configure.ac by @dimpase in
+  https://github.com/semigroups/Semigroups/pull/944
+* fix the URL for libsemigroups in README.md by @dimpase in
+  https://github.com/semigroups/Semigroups/pull/945
+* kernel: fix mem leaks by @james-d-mitchell in
+  https://github.com/semigroups/Semigroups/pull/951
+
 ### Version 5.2.1 (released 05/03/2023)
 
 This is a minor release with some changes for compatibility with upcoming
diff --git a/PackageInfo.g b/PackageInfo.g
index b27d3c3d6..47f06d461 100644
--- a/PackageInfo.g
+++ b/PackageInfo.g
@@ -34,8 +34,8 @@ _STANDREWSCS := Concatenation(["Jack Cole Building, North Haugh, ",
 SetPackageInfo(rec(
 PackageName := "Semigroups",
 Subtitle := "A package for semigroups and monoids",
-Version := "5.2.1",
-Date := "05/03/2023",  # dd/mm/yyyy format
+Version := "5.3.0",
+Date := "18/09/2023",  # dd/mm/yyyy format
 License := "GPL-3.0-or-later",
 
 ArchiveFormats := ".tar.gz",
diff --git a/VERSIONS b/VERSIONS
index ba76aec45..6fd296228 100644
--- a/VERSIONS
+++ b/VERSIONS
@@ -1,7 +1,7 @@
 #############################################################################
 ##
 ##  VERSIONS
-##  Copyright (C) 2011-2022                              James D. Mitchell
+##  Copyright (C) 2011-2023                              James D. Mitchell
 ##
 ##  Licensing information can be found in the README file of this package.
 ##
@@ -9,6 +9,7 @@
 ##
 ##
 
+release 5.3.0  - 18/09/2023
 release 5.2.1  - 05/03/2023
 release 5.2.0  - 01/12/2022
 release 5.1.0  - 31/10/2022