I'm the senior dev on my team, and whenever a new dev joined my team they would look at the codebase and go "ew, python2? Just use python3."
That gave me a chance to explain the testing and refactoring cost that would come with changing python versions, and how the benefits to users would be almost zero. And then at some point one of the new juniors said, "hey, there's a lot of filesystem performance improvements and readability improvements (f-strings) in 3. I can get the test/refactor done in a month, and I think it's a net positive." They were right, and now we're on python3.
That gave me a chance to explain the testing and refactoring cost that would come with changing python versions, and how the benefits to users would be almost zero. And then at some point one of the new juniors said, "hey, there's a lot of filesystem performance improvements and readability improvements (f-strings) in 3. I can get the test/refactor done in a month, and I think it's a net positive." They were right, and now we're on python3.
So, sometimes we all learn something.