There is a new post about the changes.
If you wish to continue working through the (now-archived) previous curriculum, your progress has not been erased. You can absolutely continue going through these older challenges, you will just need to scroll down a little further on the map. However, I do want to caution that the archived content is no longer being actively updated, so for the latest and greatest information I encourage you to check out the Full Stack curriculum.
https://forum.freecodecamp.org/t/reorganised-learning-path/738831