lightroom catalog

[Loriot 2.0]

Hello

The following situation occurs: I have lightroom classic on iMac os Monterey. One on MacBook Air os sequoia 15.1.1 . My photos and Lightroom catalog are on external SSD disk. The last few weeks I have been working on my MacBook Air. Now I recently reconnected my external disk to iMac and get the message that the catalog is not compatible with the os version on iMac and I have to update the operating system to a later version, but my iMac can no longer be updated to a later version of os. Is there a solution for this? Or do I have to create two separate catalogs, one for iMac and one for MacBook Air?
This probably means that I have double work with entering keywords. Or is there another solution?

Thanks for your answer.

[dj_paige]

get the message that the catalog is not compatible with the os version on iMac

Are you sure it didn't say something like the catalog cannot be opened because it is from a newer version of LrC??

If your iMac can run newer versions of LrC, then update LrC. If your iMac can't run newer versions of LrC  (perhaps because the operating system is too old and can't be updated), then I would imagine there is no solution (other than getting a new computer)

[Loriot 2.0]

ok thanks.