Nextcloud mise à jour sous mac os X

sorry i dont understand anything…
i use mac os X Mojave 10.14.5 and nextcloud 2.3.3 built 84, and also nextcloud on the iphone
it says every day to me “you have to update”
when i open the parameters of nextcloud it says “interrogation of the servor for updates” and it remains so, therefore i dont’ know what is the way to upgrade
would you give me any tipps ?