I've initially learned PHP4 when PHP3 was still used. Later I learned PHP 5 which iirc was the first version which had classes. I also learned Drupal 6 and then

I've initially learned PHP4 when PHP3 was still used. Later I learned PHP 5 which iirc was the first version which had classes. I also learned Drupal 6 and then 7. Modern PHP code looks nothing like PHP code back then. Of course, the core syntax is mostly the same, but if you look at a framework like D6 or D7 no one would do anything even remotely like this today. PHP security has completely changed since then as well.