"irrevocable" isn't the 1.0a problem, "authorized" is. BRP OGL specifically rewrites that section (section 10 there) to explicitly make products published from

"irrevocable" isn't the 1.0a problem, "authorized" is. BRP OGL specifically rewrites that section (section 10 there) to explicitly make products published from older versions retain the older license - you can sell a product published with an older BRP OGL. The authorization question with Hasbro's OGL is whether 1.0a products lose their license because Hasbro allegedly deauthorizes it in 1.1. Also their license FAQ spells out the Arthurian limits (you can, just not commercially with their system in a BRP OGL product).