## v19, implemented by >= 0.9.22
-New proplist field for sink input, source output introspection opcodes and at the end:
+New flag at the end of sink input and source output introspection data:
bool corked
+## v20, implemented by >= 1.0
+
+Two new flags at the end of sink input introspection data:
+
+ bool has_volume
+ bool volume_writable
+
+## v21, implemented by >= 1.0
+
+Changes for format negotiation in the extended API.
+
+New fields PA_COMMAND_CREATE_PLAYBACK_STREAM:
+
+ uint8_t n_formats
+ format_info format1
+ ...
+ format_info formatn
+
+One new field in reply from PA_COMMAND_CREATE_PLAYBACK_STREAM:
+
+ format_info format
+
+New fields in reply from PA_COMMAND_GET_SINK_INFO (and thus
+PA_COMMAND_GET_SINK_INFO_LIST)
+
+ uint8_t n_formats
+ format_info format1
+ ...
+ format_info formatn
+
+One new field in reply from PA_COMMAND_GET_SINK_INPUT_INFO (and thus
+PA_COMMAND_GET_SINK_INPUT_INFO_LIST)
+
+ format_info format
+
+## v22, implemented by >= 1.0
+
+New fields PA_COMMAND_CREATE_RECORD_STREAM:
+
+ uint8_t n_formats
+ format_info format1
+ ...
+ format_info formatn
+
+One new field in reply from PA_COMMAND_CREATE_RECORD_STREAM:
+
+ format_info format
+
+New fields in reply from PA_COMMAND_GET_SOURCE_INFO (and thus
+PA_COMMAND_GET_SOURCE_INFO_LIST)
+
+ uint8_t n_formats
+ format_info format1
+ ...
+ format_info formatn
+
+Five new fields in reply from PA_COMMAND_GET_SOURCE_OUTPUT_INFO (and thus
+PA_COMMAND_GET_SOURCE_OUTPUT_INFO_LIST)
+
+ format_info format
+ volume
+ bool mute
+ bool has_volume
+ bool volume_writable
+
+## v23, implemented by >= 1.0
+
+New field in PA_COMMAND_UNDERFLOW:
+
+ int64_t index
+
+## v24, implemented by >= 2.0
+
+New field in all commands that send/receive port introspection data
+(PA_COMMAND_GET_(SOURCE|SINK)_OUTPUT_INFO,
+PA_COMMAND_GET_(SOURCE|SINK)_OUTPUT_INFO_LIST):
+
+ uint32_t available
+
+The field is added once for every port.
+
+## v25, implemented by >= 2.0
+
+When port availability changes, send a subscription event for the
+owning card.
+
+#### If you just changed the protocol, read this
+## module-tunnel depends on the sink/source/sink-input/source-input protocol
+## internals, so if you changed these, you might have broken module-tunnel.
+## Don't forget to test module-tunnel-{source,sink} when pushing protocol
+## changes.