Twenty years after its introduction, the jQuery team has released version 4.0.0. The first major release in almost 10 years brings significant improvements, modernizations, and breaking changes. Many users can upgrade with minimal changes to their code. Version 4.0.0 is intended to mark a new phase for the JavaScript library. The release follows a long development cycle with several pre-releases. The breaking changes are changes that the team has wanted to implement for years but was unable to do so in patch or minor releases.