Bootstrap, the most widely used open source front-end component library on the web, has adopted a new Long Term Support plan that will make the development cycle a little more predictable. From now on, each major version will receive at least six months of support after it is retired, followed by six months of critical bug fixes and security updates before transitioning to Maintenance.

The Bootstrap development team moved version 3 to end of life this week and plans to move version 4 to LTS after releasing v4.4. LTS versions will generally not get new features but may still receive bug fixes, security updates, and documentation updates.

Meanwhile, version 5 is currently under active development and its initial release date has not yet been set.

BuiltWith ranks Bootstrap as the most popular technology among design frameworks in use across the internet. HTML5 Boilerplate, the next most popular, has roughly a third of Bootstrap’s market share. According to W3Techs, Bootstrap.js is used by 25.4% of all the websites whose JavaScript library it can detect, an estimated 19.3% of all websites.

Hundreds of WordPress plugins and themes implement Bootstrap in one way or another. Depending on how they include the framework and which versions they support, developers will want to note the changes with Bootstrap’s new LTS plan. It provides a definitive guide to the development life cycle, helping those in the surrounding ecosystem make better decisions about which versions to support in their projects and how long. The LTS dates are not set in stone but Bootstrap’s development team said they are working on strengthening timeline assurances.