https://github.com/bitshares/bitshares-2/releases/tag/v2.0.151209List of changes
Market mechanics changes
Refund order fee on cancellation #445
Prevent margin call from executing unless feed < call #436
Improvements
Several API calls added by community members (wackou, Scott Howard) #339
Add propose_builder_transaction2 RPC
Bugfixes
Fix referral reward percentages #449 #453 #455
Improve wallet fee handling #434 #435
Minor improvements to Javascript integration #439
Unit testing improvements / bugfixes #413 #437