See the How to set the first day of the week? ticket.
Documentation - The TcxFilterOperatorKind type declaration contains the fcoLast7Days value rather than foLast7Days
Answers approved by DevExpress Support
We have fixed the issue described in this ticket and will include the fix in our next maintenance update. To apply this solution before the official update, request a hotfix by clicking the corresponding link for product versions you require.
Note: Hotfixes may be unavailable for beta versions and updates that are about to be released.