In order to ensure that Desktop Notifications continue to work following an upgrade to Desktop v4.3.0 (due to security related updates), changes needed to be made in the Webapp (v5.16). These changes now need to be ported back so that anyone updating to Desktop v4.3.0 that is still on 5.15, 5.14 and ESV (5.9) will continue to have fully functional Desktop Notifications.
One note for QA: there shouldn't be notification compatibility issues if servers are upgraded to the backported server versions but still using v4.2 or earlier, but QA should verify.
No testing required.
I tested notifications on desktop app 4.3 RC2 (on Mac) on 5.15.1, 5.14.4 and 5.9.5. The only issue I encountered was when clicking on notifications I wasn't brought directly to the posts on 5.14.4 and 5.9.5. Mattermost came into focus as expected each time but it just didn't go directly to the channel where the mention was made from.
I filed MM-19259 to address the above.
Steve and Lindy are re-testing this.
Re-tested on Win10, desktop app 4.3 RC5 on 5.15.1, 5.14.4 and 5.9.5 and did not find any issues. Desktop notifications fire as expected per settings set in Account Settings.
Retested on macOS DEsktop Version 4.3.0-rc5 (4.3.0-rc5.3228) and did not find any issues. All notifications working as expected.