Php Issue on Mac Upgrade

Hi, I have some local sites for dev on my Mac that are the latest version of EE2. Not updated for years and clients for various reasons don’t want to upgrade to EE5. Fair enough.

Now they want some changes but when I go to access the sites I get a blank page - this is because I’ve upgraded to MacOS Mojave since last accessing those EE2 sites and it is running PHP Version 7.1.33.

I assume this is the issue. All EE5 sites work fine but I have a feeling that EE2 should work with Php7 - maybe is an add-on issue?

Any suggestions for troubleshooting?