How to know you are using classic vi
Version 3.7, 6/7/85.
Yes. 1985. 22 years.
On a contemporary computer, it will probably look like this:
Version 4.0 (gritter) 12/25/06
(The given date will vary.) This is Gunnar Ritter’s lightly modernised fork – but still the classic vi.
Any other response means you are using a clone.