We've had quite a few requests for this as well. Even lost a few clients because they couldnt set the start of the week day for the Cal. This would be great to have!

Hello,

At the moment this setting is determined by the language setting when logging in. As an example login in and select "Deutsch" and then check your calendar. 

I think this setting should default to “Use Default” then be able to override it. We have a ton of users who’d like that start day to be Monday, but without learning a new language 😀😀

I agree, we should probably have a calendar day dropdown containing like "Based on Language" and then the options for start days.

That would be awesome Matt. Google, O365 and just about everyone else allows you to set this. I totally get relying on the localization settings for this, but it should also be able to be set/overwritten by the end-user to their personal preferences.