Alright, it says :
What's new in version 50.0.133 :
This software update For your NOOK Glowlight Plus includes the following improvements :
New design makes it easier than ever to navigate the NOOK experience.
New ways to sort, filter, and view your books based on reader feedback.
Reading progress and complete date tracking.
More personalized recommendations and category-specific shopping.
Additional fixes and improvements.
Thank you for using NOOK !
They obviously did a bunch of stuff here including bug fixes.
Firmware version is now 50.0.133/50.5.35 or what they call the App Version but it looks like The Shop Version and Readouts Version might have updated as well.