Can't Collaborate Due To Old Pages ?

I can barely believe I have this problem in 2022. My wife and I collaborate on a cookbook, which is shared by her on iCloud. Usually we edit on iPads, but today I decided to use my 2012 Macbook Pro (Catalina) and it cannot edit the file because the version of Pages is too old (it can open the file and display it just fine..). If I try, I get a little popup window telling me that there is a Pages update. However, the update requires Monterey. My macbook pro 2012 will not update to Monterey because reasons.

How do we save our shared cookbook in a Pages-11.1 compatible version so that I can edit on my macbook ?