[Plan] Release new version 5.0.0

Sorry, posted an empty comment unintended.

https://www.drupal.org/project/advagg/issues/3003151 is worth too. 404 pages can be broken in IE because of that bug.

Can this release be pushed out yet? My issue #3230245: Release 4.2.0 was closed as dup because of this (I searched but didn't see this) but there's been no activity for >1yr here.

I don't believe issue #3170662: Fix deprecated code in 9.1.x should hold the many already-committed fixes up from a stable release. That issue is fixing some deprecated symfony classes that when changed appear to break D8.9; it would be far better IMO to issue this release without that change and then, if and when '662 is ready, do that separately and perhaps on a 5.x branch.

With regards to #3003151: Content is not well-formed on 404 page I have commented on the currently-to-review patch; the patch seems plausible but the overall method seems to me the wrong one, and that some other way of achieving that goal should be sought. Given that IE is now falling fast on the popularity stakes (now <0.5% acc. to Statcounter), and 404 pages are never the highest priority pages on a site, I don't see any reason to require that 4.2 should include a fix for it.

Can you please add release notes that explain what changed in the release? The drupalorg-cli tool has a command for building them that works well.