Unsupported Photos Library on New Mac
I'm installing all my files and bits from a previous Mac to a new one, and everything has gone smoothly except for the Photos Library. When I click on Photos a pop-up says 'Unsupported Library' and then 'The library "Photos Library" is from a newer version of Photos. Please upgrade Photos to open this library.'
Can someone explain to me what I do here? My only options are to Quit or Open Other.. [library]. On my old Mac I've checked and everything is up to date, I can't find a newer version. So what can I do to bring all my photos onto this new device?
MacBook Air 13″, macOS 10.15