Why this extension?
This 2 in 1 module recommends looking for similar items when product is out of stock and disables the Add to Cart Button and replace it with Out of Stock (On Product Page Only).
This does not show for products that are in stock.

(This Demo shows the recommendation links but not Out of stock button)

Once you click the recommendation link the module then searches the store for other products with the same model number or product name that are in stock.
This ensures that the customer lands on the exact same products that they were interested in, this time in stock so they can happily make a purchase. (Currently set to Model Number, hit Get Support and I will update with product name for free.)
This notice can be potentially be added anywhere on the product page.



This module is especially great for multi-vendor environments where you have vendors selling the same items or if you use a single model number scheme for all items in a category instead of the real model number - For example, all laptops regardless of brand would have the model number: STORE-LAPTOP (Just an example)


Compatibility
This module was made in .ocmod format so it doesn't override core files
This module was tested with the default 3X theme only
Works with multi-store
For custom theme or personal adjustments, please contact us, we charge a small fee.

More extensions from Nightwing
1) You might be interested in: Out Of Stock Product Recommendation (Using Primary Category)
Where it uses the product primary category recommend similar products
2) See all my other free and paid extensions: Visit Nightwing's Opencart Store

Documentation
To install this module:
Go to Extension > Installer upload the .ocmod.zip file
Go to Extension > Modifications> Refresh Modification
Go to Dashboard then clear both theme and SAAS Cache.
Go to an out of stock product page and refresh

Hit the Get Support button for free remote installation support via Teamviewer/Anydesk. (No FTP or dedicated Admin Access Required).