I recently visited Nan immigration to renew my visa, I’m married to a Thai woman. When I was there they advised me that I need to update the bankbook of the account holding my required 400,000 baht at least once a month for the 4 months preceding my renewal application. I hadn’t, so I had to get a letter from the bank with a statement regarding my account.
I’m not referring to the regular letter of guarantee, this is a different second letter.
I don’t know if this rule was in place previously at other locations. I just thought I’d give everyone a heads up just in case.