Products' Options' Stock Manager

v5.0.0 and later of POSM is distributed as a Zen Cart encapsulated plugin. Before installing this version (especially if you are updating from a version prior to v5.0.0), make sure you read this online article that identifies core-file changes that might be required and how to upgrade from a non-encapsulated version.

This plugin (POSM) provides a method for you to assign stock levels for your products based on product-attribute combinations (also known as "product variants" or "stock by attributes"). For example, if you sell T-shirts with sizes of Small, Medium and Large, this plugin enables you to specify that there are 3-Small, 4-Medium and 2-Large currently in stock — and then manages those stock levels for you. That's the easy part, what if you have a product that has three (3) options:

1. Size: Small, Medium and Large
2. Color: Black, White, Red, Blue and Pink
3. Trim-color: Black, White, Red, Blue and Pink

You don't actually stock all 75 option-combinations for this product, just a select subset. The Products' Options' Stock Manager (POSM) allows you to choose which option-combinations you actually stock and want to manage.

Each managed option can be configured to have a unique Model/SKU and a customized out-of-stock message. If you choose, managed products with multiple options are handled as dependent attributes on the product's detailed information page!

The plugin, starting with v2.2.0, also provides handlers to enable you to import and export your store's POSM configuration using the Database I/O Manager! That should make some people's jobs a little bit easier.

You can see the storefront side of POSM in action on my demo site; click here to view a list of different POSM-managed products.

Notes:

1. This version of POSM, now a Zen Cart encapsulated plugin, has been validated on Zen Cart versions 1.5.8a through 2.0.1 and PHP versions 7.4 through 8.3.
2. Not supported for stores using templates purchased from either Template Monster or Theme Forest.
3. The minimum Zen Cart version supported is v1.5.8a.
4. The minimum PHP version supported is 7.4.
5. A fresh installation of this plugin will update your database so that all product quantities are greater than or equal to 0.
6. Products whose individual option-combinations (a.k.a variants) are managed by POSM must have their Product Qty Min/Unit Mixed value set to "No" in their product-edit screen, especially when your store's Configuration :: Stock :: Allow Checkout is set to false. Once the plugin is installed, its admin-level initialization script forces all products that are POSM-managed to this setting.
7. POSM has been designed to work hand-in-hand with Edit Orders, maintaining your store's option-combinations' stock levels during the editing process. The POSM admin-level installation checks to see if EO is configured and, if so, that the Edit Orders plugin version is at least 4.1.7. If an incompatibility is detected, an admin-level warning will be displayed until the issue is resolved.
8. A configuration setting is provided to enable POSM to check that any back-in-stock dates you've configured aren't within their expiration "window". If any such dates are found, an admin-level warning is displayed.

POSM versions 2.0.0 and later support extensions, the first of which is Products' Options' Stock Manager — Price/Weight!

The plugin also provides a script to allow you to convert your existing "Stock by Attributes (SBA)" configuration into its POSM equivalent!

For the full details, please refer to the plugin's readme — accessed by clicking the "Readme" button above.