RemiAcyba: I anstalled the update (starter_v6.1.5_2019-06-10_12-21-19) as well, and it is NOT WORKING propperly.
The queue does not sent the items automatically (so, as before).
Stop/resume of the queue does not make the system send mails also.
Chnaged compeared to before:
I can now use the button "send now" in the queue. Then the emails are sent.
The message from the previus version "There is nothing to send" is not displayed anymore.
I performed als a complete new installation on a test site as well. I.e. started with a blank site - not updated from the last ACYmailing version.
May it's helpful: My server is at UTC+1h