Quote Originally Posted by Shop Suey View Post
Every Zen Cart version has a README with recommended PHP settings.

If you can't find a README you could look at github and search for older releases. There always is a README. Zen Cart is well documented.

I looked it up for you.
-> https://github.com/zencart/zencart/releases
-> https://github.com/zencart/zencart/blob/v158/README.md
Even quicker is to go to https://docs.zen-cart.com/ and click on Server Requirements. The docs are your friend.