[postfix] unsupported dictionary type: hash
It seems Postfix 3.5.9-r0 from edge has no builtin support for the (default) hash dictionary type. I cannot find any postfix-hash package or related.
I had to revert to alpine 3.11 which offers postfix 3.4.12-r0 which works.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information