since the last major version increase or the API was added.
The last version increases were:
-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
+libavcodec: 2021-04-27
+libavdevice: 2021-04-27
+libavfilter: 2021-04-27
+libavformat: 2021-04-27
+libpostproc: 2021-04-27
+libswresample: 2021-04-27
+libswscale: 2021-04-27
+libavutil: 2021-04-27
API changes, most recent first:
+2021-04-27 - xxxxxxxxxx - lavc yyyyyyyyy - avcodec.h
+ Constified AVCodecParserContext.parser.
+
+2021-04-27 - xxxxxxxxxx - lavd yyyyyyyyy - avdevice.h
+ The av_*_device_next API functions now accept and return
+ pointers to const AVInputFormat resp. AVOutputFormat.
+
+2021-04-27 - xxxxxxxxxx - lavd yyyyyyyyy - avdevice.h
+ avdevice_list_input_sources and avdevice_list_output_sinks now accept
+ pointers to const AVInputFormat resp. const AVOutputFormat.
+
+2021-04-27 - xxxxxxxxxx - lavf yyyyyyyyy - avformat.h
+ av_find_best_stream now uses a const AVCodec ** parameter
+ for the returned decoder.
+
+2021-04-27 - xxxxxxxxxx - lavc yyyyyyyyy - codec.h
+ avcodec_find_encoder_by_name(), avcodec_find_encoder(),
+ avcodec_find_decoder_by_name() and avcodec_find_decoder()
+ now return a pointer to const AVCodec.
+
+2021-04-27 - xxxxxxxxxx - lavf yyyyyyyyy - avformat.h
+ Constified AVFormatContext.*_codec.
+
+2021-04-27 - xxxxxxxxxx - lavf yyyyyyyyy - avformat.h
+ Constified the pointers to AVInputFormats and AVOutputFormats
+ in AVFormatContext, avformat_alloc_output_context2(),
+ av_find_input_format(), av_probe_input_format(),
+ av_probe_input_format2(), av_probe_input_format3(),
+ av_probe_input_buffer2(), av_probe_input_buffer(),
+ avformat_open_input(), av_guess_format() and av_guess_codec().
+ Furthermore, constified the AVProbeData in av_probe_input_format(),
+ av_probe_input_format2() and av_probe_input_format3().
+
+2021-04-19 - xxxxxxxxxx - lavu 56.74.100 - tx.h
+ Add AV_TX_FULL_IMDCT and AV_TX_UNALIGNED.
+
+2021-04-17 - xxxxxxxxxx - lavu 56.73.100 - frame.h detection_bbox.h
+ Add AV_FRAME_DATA_DETECTION_BBOXES
+
2021-04-06 - xxxxxxxxxx - lavf 58.78.100 - avformat.h
Add avformat_index_get_entries_count(), avformat_index_get_entry(),
and avformat_index_get_entry_from_timestamp().