mobile and Macbook versions are incompatible

And “a new Mac” doesn’t have to be the latest and greatest. If budget is a problem for buying a new M4 Mac, be aware that the pro-level M2 and M3 Macs are more than powerful enough for editing phone pictures with Lightroom, and they’re available for much more reasonable prices either refurbished/used, or new and highly discounted.

I have a 2015 Mac

By @Divine_wanderer5E56

At 10 years, you’ve been fortunate to have a Mac that’s had a very good run. But it’s completely expected that options for getting the latest software have gotten very limited at the 10 year mark.

It’s been pretty consistent in recent years that after about 7 or 8 years from a Mac model’s release date, Apple will drop OS update support, and that’s when that Mac will start to not meet some system requirements of various applications. So unfortunately, if we want to keep running the latest software, we do have to time our budgets so that around 7 years after buying the last Mac, we’ll have enough money saved up or financing lined up to replace that Mac. 

Features like Adaptive Profiles that use AI rely on recent hardware technology and certain graphics features that aren’t on the old Intel Macs. On the other hand, the graphics hardware in Apple Silicon Macs is very well suited for the latest AI-assisted features. I’m saying this because if they made it possible for features such as Adaptive Profiles to run on a 10-year-old Intel Mac, it would probably run very slowly. (The graphics hardware in recent iPhones is similar to what is in an Apple Silicon Mac, so an iPhone has no problem with these features compared to an old Mac.)

You can do two things. Either accept that a 10 years old Mac won't run the latest version of Lightroom, so your phone and your Mac won't be compatible, or get a new Mac.