Add PostgreSQL migration guide links (#8497)

* Add migration guide links

* Update deprecated-features.rst

* Update mattermost-v11-changelog.md

* Update important-upgrade-notes.rst

* Update software-hardware-requirements.rst

* Update important-upgrade-notes.rst

* Update software-hardware-requirements.rst

* Update software-hardware-requirements.rst

Author: amyblais

source/administration-guide/upgrade/important-upgrade-notes.rst

@@ -26,7 +26,8 @@ We recommend reviewing the `additional upgrade notes <#additional-upgrade-notes>
 |                                                    | Experimental Bleve Search functionality has been retired. If Bleve is enabled, search will not work until ``DisableDatabaseSearch`` is set to ``false``. See     |
 |                                                    | more details in `this forum post <https://forum.mattermost.com/t/transitioning-from-bleve-search-in-mattermost-v11/22982>`__.                                    |
 |                                                    +------------------------------------------------------------------------------------------------------------------------------------------------------------------+
-|                                                    | Support for MySQL has ended. See more details in `this forum post <https://forum.mattermost.com/t/transition-to-postgresql/19551>`__.                            |
+|                                                    | Support for MySQL has ended. Our `Migration Guide <https://docs.mattermost.com/deployment-guide/postgres-migration.html>`__ outlines the steps, tools and        |
+|                                                    | support available for migrating to PostgreSQL. See more details in `this forum post <https://forum.mattermost.com/t/transition-to-postgresql/19551>`__.          |
 |                                                    +------------------------------------------------------------------------------------------------------------------------------------------------------------------+
 |                                                    | The ``registerPostDropdownMenuComponent`` hook in the web app’s plugin API has been removed in favour of ``registerPostDropdownMenuAction``. See more details in |
 |                                                    | `this forum post <https://forum.mattermost.com/t/deprecating-a-post-dropdown-menu-component-plugin-api-v11/25001>`__.                                            |

source/deployment-guide/software-hardware-requirements.rst

@@ -92,7 +92,7 @@ Database software
 
 -  PostgreSQL 14.0+
 
-Amazon Aurora equivalents of PostgreSQL is also supported.
+Amazon Aurora equivalents of PostgreSQL is also supported. Our `Migration Guide <https://docs.mattermost.com/deployment-guide/postgres-migration.html>`__ outlines the steps, tools and support available for migrating from MySQL to PostgreSQL.
 
 .. important::
 

source/product-overview/deprecated-features.rst

@@ -21,7 +21,7 @@ Mattermost Server v11.0 (October 2025)
 - The ``TeamSettings.ExperimentalViewArchivedChannels`` setting has been deprecated. Archived channels will always be accessible, subject to normal channel membership. The server will fail to start if this setting is set to ``false``. To deny access to archived channels, mark them as private and remove affected channel members. See more details in `this forum post <https://forum.mattermost.com/t/viewing-accessing-archived-channels-v11/22626>`__.
 - Playbooks has stopped working for Team Edition. Entry, Professional, Enterprise, and Enterprise Advanced plans are automatically upgraded to Playbooks v2 with no expected downtime. See more details in `this forum post <https://forum.mattermost.com/t/clarification-and-update-on-the-playbooks-plugin-v11/25192>`__.
 - Experimental Bleve Search functionality has been retired. If Bleve is enabled, search will not work until ``DisableDatabaseSearch`` is set to ``false``. See more details in `this forum post <https://forum.mattermost.com/t/transitioning-from-bleve-search-in-mattermost-v11/22982>`__.
-- Support for MySQL has ended. See more details in `this forum post <https://forum.mattermost.com/t/transition-to-postgresql/19551>`__.
+- Support for MySQL has ended. Our `Migration Guide <https://docs.mattermost.com/deployment-guide/postgres-migration.html>`__ outlines the steps, tools and support available for migrating to PostgreSQL. See more details in `this forum post <https://forum.mattermost.com/t/transition-to-postgresql/19551>`__.
 - The ``registerPostDropdownMenuComponent`` hook in the web app’s plugin API has been removed in favour of ``registerPostDropdownMenuAction``. See more details in `this forum post <https://forum.mattermost.com/t/deprecating-a-post-dropdown-menu-component-plugin-api-v11/25001>`__.
 - The web app is no longer exposing the `Styled Components <https://styled-components.com/>`__ dependency for use by web app plugins. See more details in `this forum post <https://forum.mattermost.com/t/removing-styled-components-export-for-web-app-plugins-v11/25002>`__.
 - Omnibus support has been deprecated. The last ``mattermost-omnibus`` release was v10.12. See more details in `this forum post <https://forum.mattermost.com/t/mattermost-omnibus-to-reach-end-of-life-v11/25175>`__.

source/product-overview/mattermost-v11-changelog.md

@@ -33,7 +33,7 @@
  - The ``TeamSettings.ExperimentalViewArchivedChannels`` setting has been deprecated. Archived channels will always be accessible, subject to normal channel membership. The server will fail to start if this setting is set to ``false``. To deny access to archived channels, mark them as private and remove affected channel members. See more details in [this forum post](https://forum.mattermost.com/t/viewing-accessing-archived-channels-v11/22626).
  - Playbooks has been deprecated from Team Edition. Entry, Professional, Enterprise, and Enterprise Advanced plans are automatically upgraded to Playbooks v2 with no expected downtime. See more details in [this forum post](https://forum.mattermost.com/t/clarification-and-update-on-the-playbooks-plugin-v11/25192).
  - Experimental Bleve Search functionality has been retired. If Bleve is enabled, search will not work until ``DisableDatabaseSearch`` is set to ``false``. See more details in [this forum post](https://forum.mattermost.com/t/transitioning-from-bleve-search-in-mattermost-v11/22982).
- - Support for MySQL has ended. See more details in [this forum post](https://forum.mattermost.com/t/transition-to-postgresql/19551).
+ - Support for MySQL has ended. Our [Migration Guide](https://docs.mattermost.com/deployment-guide/postgres-migration.html) outlines the steps, tools and support available for migrating to PostgreSQL. See more details in [this forum post](https://forum.mattermost.com/t/transition-to-postgresql/19551).
  - The ``registerPostDropdownMenuComponent`` hook in the web app’s plugin API has been removed in favour of ``registerPostDropdownMenuAction``. See more details in [this forum post](https://forum.mattermost.com/t/deprecating-a-post-dropdown-menu-component-plugin-api-v11/25001).
  - The web app is no longer exposing the [Styled Components](https://styled-components.com/) dependency for use by web app plugins. See more details in [this forum post](https://forum.mattermost.com/t/removing-styled-components-export-for-web-app-plugins-v11/25002).
  - Omnibus support has been deprecated. The last ``mattermost-omnibus`` release was v10.12. See more details in [this forum post](https://forum.mattermost.com/t/mattermost-omnibus-to-reach-end-of-life-v11/25175).