The backwards compatibility has broken some - I think mostly visibly noticeable between 5.6 and 7.0. And every release there's some deprecations introduced tha

The backwards compatibility has broken some - I think mostly visibly noticeable between 5.6 and 7.0. And every release there's some deprecations introduced that will eventually break in future. Many complex applications in 5.6 won't run 100% error free in 8.2, for sure. I'm working with a company to move from 5.6 to 7.4 and there's very little that doesn't work in the main code. Their earlier version of Doctrine was using a class called 'Null', and internally (unrelated to doctrine) they had a class named 'Null' - those had to be renamed. That took all of about 2 minutes. Upgrading Doctrine version got us to a version that removed the Null class name there too. Python also broke backwards compatibility with their v3 release years ago. Unsure why breaking backward compatibility is being called out here(?). But yeah, overall, it's struck me that PHP has introduced more and stricter typing rules with surprisingly little impact (compared to what could have been, of course).