I suppose <2.7 then. I was thrown off by "...every good thing must come to an end; Python 2.7 was going end of life.", implying that the product was written for 2.7 and was hence facing its deprecation problem.
Python 2.7 was the last of the Python 2.x releases. They likely started with an earlier version, kept upgrading to 2.7 and then had to bite the bullet and actually rework it for Python 3.x (which is a highly similar but different programming language). Which is why that quote makes sense.