You mean, there are still bugs in 5.4.4 UE from August 27 and you can't use it?
https://forums.unrealengine.com/t/5-4-4-hotfix-released/1993894
Yes there was issues, issues that required more time than I could dedicate due to other projects sadly. We have a build using 5.4, but it would be silly to release it in the state its in as we only release working prototypes that can be played by all.
Its always been a pain migrating to newer versions of the engine, as is the case with most projects in UE. This time we have paid projects that take the lead in the que of work. If we work away getting 5.4 working now, 5.5/megalights etc, will be requested, so time will be best used on 5.5. Im solo on this, so its hard to split myself sometimes.
Sorry for delays, but it will be worth it :)