API changes, most recent first:
+2015-xx-xx - xxxxxxx - lavc 57.9.1 - avcodec.h
+ Deprecate rtp_callback without replacement, i.e. it won't be possible to
+ get image slices before the full frame is encoded any more. The libavformat
+ rtpenc muxer can still be used for RFC-2190 packetization.
+
2015-11-xx - xxxxxxx - lavc 57.9.0 - avcodec.h
Add AV_PKT_DATA_FALLBACK_TRACK for making fallback associations between
streams.