Backward Incompatible Changes

As we have already learned, PHP 7 is way more than just a few new features that have been added to the language. The main long-term benefit will be the changes that have been made under the hood. They will allow us to take PHP into the future for a long time to come, while still improving it further.

Well, everything comes at a price. The extensive changes behind the scenes have required some backwards-incompatible changes. Fortunately, we are mostly talking about edge cases, and many projects will not even be affected. The more you have invested into writing clean and readable code, the less you will be affected by any of the following issues.