Does this request sound related to what you are after? Trying to warn the user if their last sync time is over a threshold.
You can prevent uploads from old surveys by changing the form state to closed, this only works if you are retiring a form and not if you want the users to sync to the latest definition.
If you knew or could set your form's / definition's life, you could include some calculations that compare the end date to the current date and disable the rest of the form and show a note telling them to sync to get a different form/updated definition. eg definitions are updated on the first of the month, so if today is 2025-03-02 and the version I have is from 2025-02-01, the calculation would check that today is before 2025-03-01, and as it is not, show the warning note and disable the rest of the form.