Well, there's two ways for android. One requires you to back up the save using your built in files manager, the other requires downloading the compressed APK. If you download the Compressed instead of the 1+gig file, you can install over top of your previous installation.
With the other, you have to go into android, then data then find the CoR folder (I think it's under "Zimon" now...?) and copy all the files from that to a separate folder, then delete the app to install the new one, then open the app once, kill the app (use the square/hamburger thing, the three lines, in other words, then swipe up on CoR), then find that CoR folder again, and copy the files back into it, overwriting any newer files. Not sure that the saves work for all versions of CoR, since even Zimon said that you'd need to delete your previously existing save to use the new features without bugs in a previous post.