It seems like the idea of putting a version number in a header was already well-established when IP was first defined. I wonder who was the first to come up with the idea of versioning?
I imagine versioning 0.0.1 probably revolved around file.txt, file_2.txt, file_FINISHED.txt, file_FINISHED(1).txt, file_FINAL_REAL.txt ad infinitum…
It’s quite possible they wrote the specifications on a DEC system with automatic file versioning. Probably more like DOC.TXT;69 incrementing as they make new versions.
More information on DEC automatic file versioning: Retrocomputing Stack Exchange – Filesystems with versioning – answer
Fun! I didn’t realize that was a thing!