NYS Options Lease Non-Renewal Notice

We're coming up on the expiration for a lease. The tenant has been in place for less than 1 year. NYS requires a minimum of 30 days notice to non-renew a lease that is less than 1 year; 60 days over 1 year. We've sent a certified return receipt notice but it hasn't been claimed. Are you familiar with what is legally required for notification? If the letter remains unclaimed, then does the notice have to be handed off in person or can the tenant be notified through the rent payment app?

Any feedback is appreciated.