Adastra is finished, but they are working on Khemia and Interea, both being sequels to Adastra.
Now that Echo is done with Arches, they will be moving on to start updating Khemia as their main focus, and Interea being a smaller, side project which they’ll be updating less requently. I would suggest checking out their respective pages in the comments (Especially in Khemias)! They go into more detail about what Echo is doing.