Somebody out there who has some experience with schedule OI of form 1040NR? I didn't find an answer to this anywhere:

I am struggling with question F: "Have you ever changed your visa type (nonimmigrant status) or U.S. immigration status?"

Does 'ever' only refer to the tax year or to my entire Visa-immigration history in previous years?
During the entire tax year I was a non-resident, meaning I was not present in the U.S and had no U.S. immigration status but in the past I had many changes, including receiving and relinquishing a green card.

So what should I note down?

Any help greatly appreciated

They want the ENTIRE immigration history. However, when you answer, specify the dates.