In launcher, click beta, click patch notes.
IMAGES: http://imgur.com/a/vI4R8
Some big points we didn't already know about from LotV:
- Prologue Missions available to all in HotS
- Can purchase HotS, WoL, and LotV in-game on the campaign screen(s)
- Archon Mode added to WoL/HotS for custom games only (Ranked ladder coming with LotV)
- Sc2 Installation Files changed from .MPQ to CASC, see this for details about what it means
- Chat channel member limit increased from 100 to 200, in public channels AFKers will be kicked
- New chat filtering options added (no specifics)
- Two New Backgrounds -- Artanis and Space Clouds -- added. Can still choose Kerrigan or WoL Planets
- Automatically join Arcade Chat when visiting Arcade; can type [Lobby] in chat to link to the specific lobby you are in
- Starter Edition gets access to more stuff, like leveling to max levels
- Loading screens have new art, don't show levels, and ONLY SHOWS LEAGUE PORTRAITS FOR 1v1
- Some options made default
- All replays now autosave by default, and their filesize is now displayed
- Worker Count Text will now change red if you have 4 or more workers in a geyser
Editor
- Can now do three-way-file merges with mods and maps
- Can modify UI of map loading screens
- Spellchecker for text
- Can use MULTIPLE TEXTURE SETS FOR THE SAME MAP, as long as 2 different texture sets don't exist in the same 8x8 area -- this affects a lot, we'll be seeing more visual variety in ladder maps even
- Vison brush, can paint vision blocking directly on to map
- Data Wizards, basically extensions for the data editor
- Lots of other cool stuff that don't make sense if you don't use the editor