since the last major version increase or the API was added.
The last version increases were:
-libavcodec: 2015-08-28
-libavdevice: 2015-08-28
-libavfilter: 2015-08-28
-libavformat: 2015-08-28
-libavresample: 2015-08-28
-libpostproc: 2015-08-28
-libswresample: 2015-08-28
-libswscale: 2015-08-28
-libavutil: 2015-08-28
+libavcodec: 2017-10-21
+libavdevice: 2017-10-21
+libavfilter: 2017-10-21
+libavformat: 2017-10-21
+libavresample: 2017-10-21
+libpostproc: 2017-10-21
+libswresample: 2017-10-21
+libswscale: 2017-10-21
+libavutil: 2017-10-21
API changes, most recent first: