Old version on my son's computer

If you bought a completely new copy of v12 then you can use the separate copy of v11 on another machine, of course.

But if you upgraded from v11 to v12 at a discount, then the v11 licence is null and void as the v12 licence has replaced it. (Opus 11 will accept the Opus 12 licence should you need to drop back a version, but not simultaneously on multiple machines.)

Additional licences are available at a discount if you want to add more machines. We also allow for a "personal laptop" licence free of charge in some cases, although I don't think it would apply to a machine used by another person (but my knowledge, and the forum, are more on the technical side than the licencing side, so I may be wrong).

For more details: