https://adtmag.com/articles/2023/10/17/openjs-announces-of-nodejs-21.aspx

The OpenJS Foundation today announced the release of Node.js 21, the latest release line of the open-source, cross-platform JavaScript runtime environment and library for running web applications outside the client's browser. It replaces the Node.js 20 line, which is being promoted to long-term support (LTS). 

The Foundation manages its releases this way: Major Node.js versions have "Current" release status for six months. This gives library authors time to add support for them. Node.js 21 will be the Current release until April 2024. The Foundation says that Node.js 21 is best for early testers working in specific environments, and it recommends Node.js 20 LTS for production deployments.