In this new post to the Laravel News site they list out some of the deprecations coming in PHP 7.2 based on this RFC.

The PHP 7.2 RFC for deprecating some current functionality has been approved. The following items are included in this list and will begin throwing deprecated notices.

The list of features to be deprecated includes:

• the magic __autoload function
• the create_function function
• the (unset) cast
• the each function

Most of the things in the list are functionality that you just don't see much in recent PHP development. It could cause problems for older codebases but for those already on PHp 7 it shouldn't take much to make the necessary changes.