This feature is already available in RentRedi. Basically, currently TurboTenant only creates a new charge. When a new charge is created, the tenant can choose to pay only the rent and not pay the late fee. Next month, they could be forced to pay the late fee if landlord has enabled setting to require past dues to be paid first before paying current rent. But the leases of most landlords typically state that late fee is "added to the rent and becomes part of the rent", which means that if rent is late, then the late fee must be paid along with the outstanding rent (especially if partial payments are turned off). I am surprised this feature is not already enabled.