A bit of explanation to Wim’s message:
The time format + timezone are derived from the location where Homey thinks it sits.
Sometimes it could just not be determined somehow, and your location is set somewhere in an ocean 
It is a simple fix:
Go to location settings, move the map to set the pointer to an other timezone, wait for a minute, and then move the map again, to set the pointer to your location / somewhere in your timezone.
EDIT: time format seems different in app v6.x and v7.x
When things went well, the clock should be set to your country’s 24h format (at least that is what it should do and what I expect it to do 
)
