Hi

I am using Zen cart integration for a customer. I like to know which version is a stable and can be integrated.

Does it requires any other php modules installed in server

Nearly any version can be integrated. I did one recently using the latest stable download on the site, and had it done in fairly short order (simple design). The hardest thing about working with Zencart if you're not used to it is all the switches and flags it uses. Turning something off in one place might not have the desired result until you find the other three places that also affect it. ;)

It uses some basic modules like GD (for the catalog images mainly), but nothing out of the ordinary.

You can download latest version from their site , all included and you can find a lot of mods to enhance it