DOC-2198: add 5x LTS important banner to the top of upgrading.adoc. (#…

…2935)

* DOC-2198: add 5x LTS important banner to the top of upgrading.adoc.

* DOC-9198: update LTS message and moved message location.

changelog.md

@@ -6,8 +6,10 @@ The format is loosely based on [Keep a Changelog](https://keepachangelog.com/en/
 
 ### Unreleased
 
+
 ### 2023-10-19
 
+- DOC-2198: add 5x LTS important banner to the top of upgrading.adoc."
 - DOC-2185: added `6.7.1-release-notes.adoc` to project; updated `changelog.adoc`, `nav.adoc` and `release-notes.adoc` for the TinyMCE 6.7.1 release.
 - DOC-2191: updated both premium, non-premium and classic-mode feature demo UI issues.
 - DOC-2027: added `/modules/ROOT/partials/configuration/help_accessibility.adoc`, documenting the `help_accessibility` option; edits, re-writes and re-structuring of `help.adoc`; plus copy-edits to `keyboard-shortcuts.adoc`, `tinymce-and-screenreaders.adoc` & `accessibility.adoc`.

modules/ROOT/pages/upgrading.adoc

@@ -3,4 +3,7 @@
 :description: How to upgrade TinyMCE via Tiny Cloud, package manager options, and Self-hosted options.
 :keywords: npm, bower, composer, nuget, update, updating, upgrade, upgrading
 
+[IMPORTANT]
+https://www.tiny.cloud/long-term-support/[Learn more about TinyMCE 5 LTS] if you need to remain on TinyMCE 5 and continue to receive security updates.
+
 include::partial$install/upgrading-info.adoc[]