I hope I'm posting this to the correct forum.
My son lives a couple of thousand miles away and I thought it would be fun for us to collaborate on music through BiaB. I have Windows 2021 Pro and I bought him Mac 2020 Pro just last week (seems to be the latest versions, if not the most complete).

I sent him a song that uses _SOFTROK style but he doesn't appear to have that real style. How I can tell what I have, and what he has, so the music we share back and forth will be the same?

For that matter, how do I know what I already have for real tracks (sets) so that I can add to it without duplicating what came with 2021 Pro our of the box?

Your thoughts would be greatly appreciated.

Of course, before posting this I emailed BiaB support but didn't get a clear answer. Now, after I posting, I found in Help | What Add Ons do I Have?

This is what I'm looking for! I think we can compare the Sets and then cross reference the included Real Tracks on the PGMusic website.
Presumably, each Set (Windows and Mac) includes the same real tracks.

I believe you are correct. The same year BIAB should have the same styles. You can identify the newest products by sorting and avoid using the 2021 offerings until your son gets the Mac upgrade.

Each identical RealTracks Set number is the same in both the Windows and Mac versions.

In addition, the identical PAKs for the Windows and Mac versions would have the same RealTracks included in the PAK as long as they have the same version/year. So the Windows 2020 Pro would have the same RealTracks as the Mac 2020 Pro. However, the latest Windows version available for purchase is 2021 and the Mac version is 2020. So the current Windows PAKs for sale will have more RealTracks than their Mac PAK equivalents. The 2021 for Mac is expected to be released in Springtime or later, but we cannot guarantee this.