Time - Timekeeping Lock Date

Administrators can prevent timeslips from having a Date of Service earlier than the date specified in the "Timekeeping Lock Date" setting on the Admin > Timekeeping Settings page.

Legacy static timeslips automatically enforce this setting, but only really old sites still use the legacy forms.

Dynamic timeslip forms must use the Date of Service with Lock Date block to enforce this setting.

That block also allows restrictions relative to the current date, for example no date more than 30 days before the current date and/or no date more than 30 days in the future.