No licensing issues. You can download dsf files from various on line stores. As for tagging, I see this as an issue because even if you tag a dsf file with a different application, opening the files with EasyTag will show you the correct tags. If you just change one field, let say add "test" to the "commnet" field and save, EasyTag will save with no issues. MPD will not read the tags. So, if EasyTag can read the tags but upon saving something weird happens, some explanation is required.