Kobo have stated that firmware 3.5.0 will be released for the Glo, Aura and Aura HD. They state the improvements as:
- Better Annotations Experience
- Various Bug Fixes
- Stability Improvements
Here is my list of changes I saw during the beta process:
- Annotations list
- completely updated
- Most of this was in 3.4.1, but some things didn't work well
- New Adobe RMSDK
- Support for new Adobe DRM
- Long paragraph bug is fixed!
- Light state remembered across sleep, power off and connection to PC
- Search
- Radio buttons for location replaced with drop-down at end of list
- Sort options in result list
- Less flashing when scrolling in the browser
Known bug fixes:
- Long paragraphs. Yes, I mentioned it above, but it's worth repeating

- If "Track reading activity" is not selected, the reading stats tile is no longer displayed after finishing a book.
There are probably some other things, but, these are the things I noticed.