Is there a CodeIgniter 3.x roadmap?

Good evening everyone.

With the upcoming release of CI4, I am wondering if there are any plans to keep adding features to the CI3 codebase?  I am also wondering what the lifecycle of CI3 will be once CI4 is released.  Will a new project built with CI3 today need to be migrated to CI4 in very short order or will there be some CI3 security releases post CI4?

Thanks