The Minnan language in Zhangpian, Quanzhou is the oldest. Minnan dialect evolved directly from the Central Plains after two waves of immigration. The Minnan language we speak now is generally Quanzhou, followed by other close relatives such as Chaoshan, Leizhou, southern Zhejiang, Singapore and Southeast Asia. They are all extensions, so the oldest one should be Quanzhou-Zhangpian.
At present, there are still many words with the same pronunciation as classical Chinese in Minnan dialect of Zhang Quan Film Department, and their meanings are the same. For example, "Ru" means you in Zhang Quan movies, you mean it in ancient classical Chinese, and there are many similar words.