Bonjour,
The localization demo for sources and journalists now updates automatically, when a new translation is available. It no longer needs manual intervention from a human being. It happens within five minutes after the translation is committed by weblate. That is at most one hour after you stop working on translating strings in a given language, possibly sooner.
If anyone is interested I’d be happy to explain the gory details and how to verify this happens using the translation history.
If you experience problems or unexpected delays, please complain and you’ll get help 
Cheers