This version fixes some bugs of moderate severity. No more smugglers having planets ceded to them.
If you're on moddb, I'm assuming you at least know how to look up a tutorial on installing mods.
Stellaris replaces some core files that most other mods reference. You can try using SZ with another mod, but I doubt it will work smoothly.
This is the full version of the mod. It should be compatible with old saves. If you're updating from the initial release, I recommend deleting the old mod folder before installing the new version.