After uploading a new release i found that this and all our earlier release show on hackage as "GPL-2.0-only". What we have in our darcs.cabal is "GPL-2". This was always intended to mean "or later". I wanted to fix this and upload a new release that uses the new variant "GPL-2.0-or-later" that I read about in the docs. But this isn't accepted by hackage. The upload candidate page responds with darcs-2.14.4/darcs.cabal:0:0: version with tags and cabal check says Warning: These warnings may cause trouble when distributing the package: Warning: 'license: GPL-2.0' is not a known version of that license. The known versions are 2, 3. If this is not a mistake and you think it should be a known version then please file a ticket. Warning: darcs.cabal:4:33: version with tags Note we have cabal-version: 1.24 in the cabal file, otherwise we could not support older ghc versions (we currently support ghc-8.0 and later). How can I fix this?