Grandfathering/ Zoning

In a previous thread Frank talks about grandfathering and suggests getting a “Certificate of Zoning”. Does anyone know if that is the same thing as a “Zoning Verification Letter?”.

I looked at some Maine case law regarding mobile home parks and, in particular, mobile home park owners trying to replace older homes with bigger more current homes and being denied. The state supreme court looks like they sided with the municipality saying that its an “Alteration”.