Migrated a few million lines of code spread over a few apps in a couple of days to php 7. Most of the time was spent setting up docker and migrating unit tests.

Migrated a few million lines of code spread over a few apps in a couple of days to php 7. Most of the time was spent setting up docker and migrating unit tests. There were literally zero code issues. Those are properly written and engineered apps written on top of proper frameworks as any professional would write them. There is another app that depends on a php 5 library that's still running on php 5 now, three years later. So the upgrade situation is extremely easy and simple if your code isn't total shit. With shit code, the migration is the least of one's worries.