The size of additional variable data (which is a member of audio object properties within signal flow data) has been changed from 2 bytes to 4 bytes to accommodate the AI Object (which greatly exceeded 64kb). GTT and xAF are updated to handle this change – and old (previously saved) sfd files should still work. For reference the parser changed is DSFDParser.
Old files have a different chunk ID which is supported in the updated parser (it will read 2 bytes instead of 4) but new files have a new chunk ID which specifies it uses 4 bytes instead. If you try to load a new file in an old version of the framework you will get an error (because the chunk ID is unknown).
When using U release GTT with U release xaf – you will get the updated chunk ID when sending data.
U release GTT and previous xaf release will give you the old chunk ID.
Previous GTT and new xaf will also give you the old chunk ID (but it will load).