We have noticed also some strange behaivior in the gwia as we upgraded
from 7.03 towards 8.01

Some things are handled differently.

For instance:

We had to set smtp/mime- message formatting-out bound settings- MIME
and not RFC-822. (7.02hp1 had set it on rfc-822)

If we do not do that, attachments look like wierd language in other
mail systems like gmail/hotmail.

Can any give some clue on this?