diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6932d3d7c..1d13e56d6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,9 @@ All major and minor version changes will be documented in this file. Details of
 
 ## Details
 
+### [10.4.0] - 2023-03-24
+- Added 'Generate De Bruijn Sequence' operation [@gchq77703] | [#493]
+
 ### [10.3.0] - 2023-03-24
 - Added 'Argon2' and 'Argon2 compare' operations [@Xenonym] | [#661]
 
@@ -368,6 +371,7 @@ All major and minor version changes will be documented in this file. Details of
 
 
 
+[10.4.0]: https://github.com/gchq/CyberChef/releases/tag/v10.4.0
 [10.3.0]: https://github.com/gchq/CyberChef/releases/tag/v10.3.0
 [10.2.0]: https://github.com/gchq/CyberChef/releases/tag/v10.2.0
 [10.1.0]: https://github.com/gchq/CyberChef/releases/tag/v10.1.0
@@ -519,6 +523,7 @@ All major and minor version changes will be documented in this file. Details of
 [@brun0ne]: https://github.com/brun0ne
 [@joostrijneveld]: https://github.com/joostrijneveld
 [@Xenonym]: https://github.com/Xenonym
+[@gchq77703]: https://github.com/gchq77703
 
 [8ad18b]: https://github.com/gchq/CyberChef/commit/8ad18bc7db6d9ff184ba3518686293a7685bf7b7
 [9a33498]: https://github.com/gchq/CyberChef/commit/9a33498fed26a8df9c9f35f39a78a174bf50a513
@@ -635,4 +640,5 @@ All major and minor version changes will be documented in this file. Details of
 [#1499]: https://github.com/gchq/CyberChef/pull/1499
 [#1528]: https://github.com/gchq/CyberChef/pull/1528
 [#661]: https://github.com/gchq/CyberChef/pull/661
+[#493]: https://github.com/gchq/CyberChef/pull/493