Languages don't work in 4.4

Hi,

Since I’ve updated CF7 to version 4.4, languages don’t work anymore.
I know the language selector has been removed, but the .po / .mo files should do the job, but they don’t.

Everything is in english even though I’m using the french language in the backend. Some strings are translated like “Create new form”, but all the form messages are still in english.

Does anyone know how to fix this? I tried making my own language files but it didn’t change much

I’m using a theme called The7, maybe there is a conflict somewhere?

https://wordpress.org/plugins/contact-form-7/