Chiang Mai immigration office has notified all school in Chiang Mai about proof of residence for all foreigner if leave from Thailand and come back have to bring proof of residence (receipt of notification or t.m.30) do update at Chiang Mai immigration within 24 hr. After come back to Thailand and can do it by yourself without fee or if move new address you have to notify to immigration within 24 hr. If notify proof of residence too late have to pay for fine 1,600 baht at immigration.

Best Wishes
RAK THAI LANGUAGE SCHOOL