Doc: Backport release notes (v2-edge)

doc/.custom_wordlist.txt

@@ -16,6 +16,7 @@ Cloudflare
 CMS
 CRUSH
 cryptographically
+CVEs
 DCO
 DHCP
 disaggregate

doc/reference/release-notes/index.md

@@ -25,9 +25,12 @@ For full instructions on updating or upgrading MicroCloud, refer to {ref}`howto-
 
 ```{toctree}
 :titlesonly:
+MicroCloud 3.4.1 LTS <https://documentation.ubuntu.com/microcloud/latest/reference/release-notes/release-notes-3.4.1/>
+MicroCloud 3.4.0 LTS <https://documentation.ubuntu.com/microcloud/latest/reference/release-notes/release-notes-3.4.0/>
 MicroCloud 3.3 <https://documentation.ubuntu.com/microcloud/latest/reference/release-notes/release-notes-3.3/>
 MicroCloud 3.2 <https://documentation.ubuntu.com/microcloud/latest/reference/release-notes/release-notes-3.2/>
 MicroCloud 3.1 <https://documentation.ubuntu.com/microcloud/latest/reference/release-notes/release-notes-3.1/>
+MicroCloud 2.1.5 LTS </reference/release-notes/release-notes-2.1.5>
 MicroCloud 2.1.4 LTS </reference/release-notes/release-notes-2.1.4>
 MicroCloud 2.1.3 LTS </reference/release-notes/release-notes-2.1.3>
 MicroCloud 2.1.2 LTS <https://discourse.ubuntu.com/t/microcloud-2-1-2-lts-has-been-released/73771/2>

doc/reference/release-notes/release-notes-2.1.5.md

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+---
+myst:
+  html_meta:
+    description: Release notes for MicroCloud 2.1.5, including highlights about new features, bugfixes, and other updates from the MicroCloud project.
+---
+
+(ref-release-notes-2.1.5)=
+# MicroCloud 2.1.5 release notes
+
+This is an {ref}`LTS release <ref-releases-microcloud-lts>` and contains bugfixes, package updates and new features.
+It's the sixth release of the 2 LTS track.
+
+(ref-release-notes-2.1.5-highlights)=
+## Highlights
+
+This section highlights new and improved features in this release.
+
+### Dependency updates
+
+MicroCloud is rebuilt against the latest LXD and MicroCeph releases, and its Go module dependencies are refreshed to pick up upstream fixes, including security fixes for known Go CVEs.
+
+(ref-release-notes-2.1.5-incompatible)=
+## Backwards-incompatible changes
+
+These changes are not compatible with older versions of MicroCloud.
+
+### Minimum system requirement changes
+
+The minimum supported version of some components has changed:
+
+* Go: 1.27.2 (used to build MicroCloud)
+
+## Upgrading to the new version
+
+If you are already using MicroCloud 2 LTS, refer to the {ref}`howto-update` guide for information on how to retrieve and use the latest release within the same major version.
+If you are on an older major version, refer to the {ref}`howto-upgrade` guide.
+
+(ref-release-notes-2.1.5-changelog)=
+## Change log
+
+View the [complete list of all changes in this release](https://github.com/canonical/microcloud/compare/2.1.4...2.1.5).