I think that “YEAR” is a standard tag for the release year of an album version. But “ORIGINALRELEASEDATE” is not standard tagging for the original date/year that an album was first released, and is unlikely to be recognised in other players. Standard practice (ID3 tags) for original year of release seems to be either ORIGINAL_YEAR, TORY or TDOR. To make matters more confusing, it appears there was (perhaps still is) an error in Roon’s implementation in that it was reading TORY and TDOR as the release date, and not the original release date.
Most good tagging software lets you add custom fields. I have been adding one for ORIGINALRELEASEDATE for Roon, and everything works well. It does not mess with any standard tags that might already exist in the files. For new files, if you want to maintain compatibility with other players (iTunes) you probably also have to also add one of the globally recognised ID3 tags (perhaps ORIGINAL_YEAR).
Another forum post that might assist…
A useful standard tag mapping table…
http://www.jthink.net/jaudiotagger/tagmapping.html
Regards
Paul