EDIT: Oops, accidentally said "in this post", when WoTC's announcement was in the FAQ that got leaked.
> Can I keep using OGL 1.0a to develop fifth edition content?
>
> No. OGL 1.0a only allows creators to use "authorized" versions of the OGL, which allows Wizards to determine which of its prior versions to continue to allow use of when we exercise our right to update the license. As part of rolling out OGL 2.0, we are deauthorizing OGL 1.0a from future use and deleting it from our website. This means OGL 1.0a can no longer be used to develop content for release.
https://www.youtube.com/watch?v=LTXkxy2KjXUIt even explicitly states "Content already released under 1.0a will also remain unaffected."
(though ideally they'd, you know, make that legally binding.)
FWIW, I don't even believe they ever wanted to try to claw back e.g. the 3.5 SRD, so I'm not as concerned as other folk here. (But it's also clear that if they have no such intent, they'd need to make it legally binding for folk to trust them.)
> Can I keep using OGL 1.0a to develop fifth edition content?
>
> No. OGL 1.0a only allows creators to use "authorized" versions of the OGL, which allows Wizards to determine which of its prior versions to continue to allow use of when we exercise our right to update the license. As part of rolling out OGL 2.0, we are deauthorizing OGL 1.0a from future use and deleting it from our website. This means OGL 1.0a can no longer be used to develop content for release.With those two bits, I expect OGL 1.1 to only allow commercial use.
They do explicitly say "Content already released under 1.0a will also remain unaffected" though!
They would lose any serious challenge in court, though i wonder how much hasbro lawyers would drag it out...