This release includes some bugfixes that were reported in 3.5.1 and a new "Save dmesg output" menu item.

Mod Store

Delete extracted hmod files if downloading a compressed version
Miscellaneous

Add "Save dmesg output" menu item
Fix for importing multi-track cue files with a single data file

New Features:

Bluetooth support with optional hmod installable from the modules window
Sega Support!
Full stock UI integration
Folders
C button acts as a folder back button
Ability to force a specific UI theme
Support for launching Genesis/MegaDrive games in stock emulator
Support for launching games in other emulators
Save compression
Save compatibility with retroarch and m2engage
Spine generator with templates by TheWez1981
Genesis/MegaDrive folder artwork by TheWez1981
Make use of additional space on the NAND that previously wasn't usable
Add SD card format to tools menu
Add ability to export and import folder structure
Add option to create save folder on usb export
Add support for other gamepads in stock ui / emulator
Get retroarch core info from hmod files
Save folder structure as html file instead of xml
Save modules report as HTML file instead of plain text
UI Changes:

Add description, genre, region, and additional player count entries to game info
Add information on common causes for taking too long to reboot
Change "Export Games" to "Export to USB"
Change dialog text when adding games to "Select games"
Change menu item text for uninstall and factory reset when shift is held
Move game count warning in folder manager into tool tip and make the label red when too many games are present
Replace references of "NES/SNES Mini" with "mini"
Set a minimum form size for mod hub
Standardize on the term "Console"
Typo: "Estimate tile left" to "Estimate time left"
Fixes:

Fix unintended scrolling when searching for images
Fix various bugs with the Google image search
Always use 228x204 for image resizing with the NES/SNES classic artwork
Fix "Group games w/ no box art" option including stock games if using their stock artwork
Fix NES fadein durations
Fix a crash when sorting by system
Fix issues scanning for box art
Fix motd links not opening in default web browser
Fix preset ID in sfrom editor to be the proper byte order
Fix problem importing legacy folders manager xml files
Fix problem when assigning core mame2003-plus to roms from UI
Fix size calculation bug if /var/saves doesn't exist
Improve sfrom generation
Return the http status code if a mod repository is unable to be loaded
Search /media/ with the select firmware dialog
Behind the Scenes:

Add menu option to developer menu to download hakchi-latest.hmod from hakchi.net
Changes to custom background hmod
Copyleft update for translation mods and external UI
Get nand partition devices based on label
Load uboot from hakchi.hmod instead of file
Make MessageForm AutoSize to the text given
Update uninstall and flash uboot to latest hakchi commands
Use custom user agent for web requests