We are getting close to the final 0.13 version. This version serves to test if there are any bugs left before making the final release.
Updates on this release:
Treat high-sigop transactions as larger rather than rejecting them (sipa)
Fix p2p-feefilter.py for changed tx relay behavior (sdaftuar)
Bugfix: Use pre-BIP141 sigops until segwit activates (GBT) (luke-jr)
https://github.com/bitcoin/bitcoin/releases/tag/v0.13.0rc3
Binary download: https://bitcoin.jonasschnelli.ch/releasebuilds/v0.13.0rc3/