Had this question too, can you clarify, so say there is an existing biz that uses some of DnD content like perks or classes; their software is said at v1.0 now,

Had this question too, can you clarify, so say there is an existing biz that uses some of DnD content like perks or classes; their software is said at v1.0 now, but then they want to include another class from existing DnD 3.5, or some perk, which would bump their release. Are they now obligated to signup for this new license, or can they just reference the old system version and license, much like a software would??