The patch also prevents the re-locking of weapon and equipment rewards after they’ve been earned, and fixes a couple of mission-specific bugs.
Players can still progress on the Companion App, but it's no longer a requirement in order to nab blue and gold chests. Which is good, because there were more than a few issues with the App after Unity launched which prevented it from working, and when it did work it minimised the game in order to launch the. So... good riddance, basically.
The PC delay is due to certain specific fixes on the platform, that will address “performance, connectivity and general stability issues.” For a full list of the non PC-specific fixes in patch 5,. Ubisoft promises to release an update on when the PC patch will drop soon.