Kernrechtsfrage
Whether the landlord's payment default notice under Art. 257d OR was sufficiently specific
Extrahierter Entscheid
Yes. It was enough that the arrears were objectively determinable; the notice identified two unpaid monthly rents and the tenant knew the payment pattern.
Extrahierte Begründung
Art. 257d OR does not require a precise numerical breakdown if the outstanding amount can be identified without doubt from the notice and the parties' payment practice.