If you don't do that, you get the python 2 to 3 transition. Which is still going on. PHP did drop some stuff between 5 and 7, but all of it had been marked dep

If you don't do that, you get the python 2 to 3 transition. Which is still going on. PHP did drop some stuff between 5 and 7, but all of it had been marked deprecated for some time prior (often years).