Does a Pennsylvania rent increase notice need to be in writing?

Yes. Pennsylvania requires a written notice for any rent increase on a month-to-month tenancy or at the end of a fixed term. Pennsylvania uses 68 P.S. 250.501 tenure-based notice: 15 days for tenancies under 1 year, 30 days for 1 year or more. No state rent cap. Rent changes on month-to-month tenancies follow the same notice ladder. An oral notice is generally not enforceable; the tenant can refuse to pay the increased amount and the landlord cannot evict for nonpayment of an unwritten increase. The written notice should state the current rent, the new rent, the effective date (which must be after the statutory notice period), and the landlord's signature. Delivery follows the same service rules as other landlord notices: personal delivery, substituted service, or posting plus mailing.

Source: 68 P.S. 250.501 (Pennsylvania Landlord and Tenant Act 1951)