I am planning up upgrading my client's site from 1.3.7 to 1.3.8 (hoping this will solve some other problems, and add the features that would be nice...)

What exactly does the Upgrade DB process do? I don't see it documented anywhere - just to run the script and select Upgrade...

Same tables, number of tables?.. So I load the DB with 1.3.7 - then the zc_install - and go the Upgrade route?...

Checking so I can plan the upgrade - and all the changes I made to the site I need to re-implement (some are to core code, most are template based... Whew!!!)

Hoping the upgrade will solve some problems with Authorize.net (error handling on some errors) and Database performance with products and attributes causing all too many db queries, 30,000 for a shopping cart of 20 items)

Thanks...
KevinW

Apart from making backups, upgrading your site involves two main steps:

• updating all your PHP files, including all your addons and customizations -- This is a manual process.
• upgrading the database -- This is a semi-automated process.

The database-upgrade step takes your existing database and applies a number of changes to it to incorporate new features and improvements to the structure and sometimes to the actual data content. Simply running the zc_install process and choosing Database Upgrade will take care of the database-upgrade portion of your site upgrade.

You have to do the files-upgrade manually.

The upgrade process is documented in both your /docs/ folder of your Zen Cart files, as well as in the FAQ section of this site: https://www.zen-cart.com/tutorials/index.php?article=98