Gordon, I don’t know how familiar you are with ubuntu, but app releases don’t always get downloaded right away. Try this link to see how you get the release channel of RT so you’re always using the latest update. Or, just switch back over to Windows and download the RT 5.4 version for that. Either way, I think that’s the key to solving your problem. Like you, I’m coming from LR . I’m not going to switch to their subscription model, so I’ve settled on RT as an alternative. I haven’t mastered it yet, but I’m a lot closer than when I started a few months ago. Bottom line: It’s powerful software that’s well worth getting to know. The documentation is really good, but there is a dearth of community-generated, high-quality resources (vids & articles) that show RT’s capabilities in real-world situations. Especially for version 5+. In any event, keep trying to solve your compatibility issue and I think it will be worth your investment of time and efforts.