bts firmware

Hi all, Perhaps it's not appropiate to ask here (first post here).... I saw on the wiki the recipee how to upgrade a ipaccess nanobts with new firmware. Well, i can probably do some experimenting with a nanobts, but how do i get hold of more recent firmware? I know this nanobts was used in a proof-of-concept trial some years ago, and needed to be upgraded at that time. After the project ended, we had no more official contact with ipaccsess, so no chance in asking them for new firmware '-) lacking some hardware features. So it would be fun if i do some experimenting at home. hw