Beyond what you described there is a weird clause in paragraph 7:
7. Updates and Runtime Restrictions. To the maximum extent permitted by law, Licensor reserves the right to restrict (remotely or otherwise) usage of the Model in violation of this License, update the Model through electronic means, or modify the Output of the Model based on updates. *You shall undertake reasonable efforts to use the latest version of the Model.*
I think this means it is now illegal to use SD 1 if at all reasonably possible to use SD 2?
“Licensor reserves the right”… the licensor has not invoked this clause and SD1.x is still listed on the huggingface repos of the respective licensors (the situation is a little complicated by the fact that 1.4, 1.5 and 2.x were each released by different licensors, so a revocation would most likely require agreement from all those parties).
Still worth keeping in mind from an open source perspective…
So for a start not being compliant with a license is not the same as something being illegal. Then I'm not sure whether the last sentence is tied to the rest of the clause if it relates to usage of the model in violation of the license. I'm not sure if v1 and v2 are considered the same model or not. Arguable either way.
It does add risks for a company sure.
edit - thanks for adding that in, it's an important part of the picture.
7. Updates and Runtime Restrictions. To the maximum extent permitted by law, Licensor reserves the right to restrict (remotely or otherwise) usage of the Model in violation of this License, update the Model through electronic means, or modify the Output of the Model based on updates. *You shall undertake reasonable efforts to use the latest version of the Model.*
I think this means it is now illegal to use SD 1 if at all reasonably possible to use SD 2?