The CakePHP team is thrilled to announce the immediate availability of 4.0.0. This is release begins a new chapter for CakePHP as 4.0 is now API stable. With this release, Cake 3.x moves into maintenance mode while 2.x moves into security release mode.

Upgrading to 4.0

While 4.0 contains a number of breaking changes we have prepared an exhaustive migration guide covering all the deprecated, removed, and new features.

Additionally, we have put together an upgrade guide which gives a step-by-step guide and CLI tool to help you upgrade your application. These documents and companion tool will only improve as we collect more feedback from people upgrading.