Hi,
First of all, let me say that I did not see lamby's patch right away. I then incorporated lamby's wishlist rating but kept the tag 'older-source-format' name. I could not find anything official that declared 1.0 deprecated. Proper credit is in the commit messages.
Like the previous patch, the MR warns on 1.0 source formats, except it also warns on implied 1.0 formats when there is no declaration. I am not sure which is better. Please let me know:
Kind regards,
Felix Lechner