Hello Yannick and community.
I entered again into a project of a website I helped developing... Back in time we migrated from sh404sef to 4SEF and 4SEO. I think we added 4SEO too as it was necessary for a correct migration in our case... Maybe due to canonical urls I think and all of this... So we have to update the plugins. We then really need 4SEO? We just want to know as actually we don't use it actively at least. So I ask you just to know that passively is doing something with us and that effectively we need it.
If you could confirm this to me would be nice...
Thank you very much. ;-)