First day of week?Browser Info Environment
It depends on the type of calendar that you are using and you have to make modification of certain PHP files. We have also changed the names of the day-of-week and the month names to german. Well almost every thing is now to our needs.
you may have a look athttp://thurgorienta.ch/kalender/... to see it in action
We have first installed this Add-on but then we needed advanced features like colored categories, etc.
That was the time when we switched to ProEvents. I have to say that dealing with international time and date formats is a little bit messy in c5. In ProEvents we had to do this changes on a calendar view by calendar view base which takes quite some time. And if there is once an update to this Add-on we have to apply all the changes we made again.
Regarding this point concrete5 could still improve.