Massively

Here are the listed changes for this release:

• SVC-1048: Forces from attachments are no longer defeated by the "landing" animation state
• SVC-1071: No-Mod objects can now be rescaled by contained scripts
• SVC-1072: Scripted objects rezzed between 1024m and 4096m altitude now work correctly
• SVC-1093: Hollow prims no longer go off-world when prim center is below terrain near a cliff
• SVC-1120: Estate Disable Collisions setting now effective on objects
• SVC-1121: No Object Entry setting now blocks object entry at parcel boundaries
• SVC-1124: Creating a Linden fern no longer crashes the simulator
• DEV-3882: Hover vehicle now turns while coasting
• DEV-5139: llTargetOmega will now rotate a non-rotating attachment
• DEV-6597: Objects no longer freeze (stick in place) when near an avatar
• DEV-7175: Rolling spheres now settle in a more natural way
• DEV-7414: Size limit checks now added to RCCS, so that objects larger than an avatar are not simplified under high physics load
• DEV-7617: Avatars no longer levitate and drop back down to platforms
• DEV-7710: Setting interpenetrating spheres to physical no longer causes simulator "deep think"
• DEV-8190: Objects now have the same mass, whether attached or not
• DEV-8351: llMoveToTarget scripted objects are now stopped at the boundary of a No Object Entry parcel (similar to SVC-1121)

Linden Lab says they're hoping for another bugfix round and refresh next Friday, with a little luck.

The whole project is geared at improving the overall stability and load-handling capacity of Second Life simulators, rather than adding new features. It's certainly done a good job so far of closing up a number of ways that physics could be exploited to crash simulators outright.

Catch up with more information about Havok4 and Second Life here.