It is official that AngularJs will no longer be developed and patched, and it is in its last LTS support mode. The original blog post https://blog.angular.io/discontinued-long-term-support-for-angularjs-cc066b82e65a
On July 1, 2018 AngularJS entered a 3 year Long Term Support period.
Due to COVID-19 affecting teams migrating from AngularJS, we are extending the LTS by six months (until December 31, 2021).
Moving AngularJS to Angular
Application build upon AngularJS should be moved to Angular. There is no easy way to move or convert an app from one framework to another, but Google provided a guideline on how to make conversions step by step.
It basically often means that the application has to be rewritten in Angular Framework.