Ardour2 session to Ardour3/4

Hi,
is it possible to convert an ardour2 session to ardour 3/4 session?
I mean: I can open an ardour2 session with ardour 4.1 but, for example, I’m not able to add AUX sends in the new 4.1 session created from the ardour2 session (menu entry is not enabled).
I don’t care about automation, buses, cross fades, plugins, etc. I’d like to have at least the audio tracks with the possibility to use all the features provided by ardour 4.1.

Thanks.

Solved. Seems that the problem is that after the import in ardour 4.1 buses aren’t recognized as buses, so the AUX send menu is greyed. Remove and recreate the buses solve the problem.