2015/10

Stores that have large numbers of out-of-stock products may not want these appearing before in-stock products. This straightforward extension allows sorting out-of-stock products to the end of category pages. Stock-based sorting is enabled or disabled per-store, and can't be configured for individual categories.

The extension uses an observer to add an extra sort clause to product collections. This will happen for every frontend collection load, not just the ones for category and search result pages, so be aware of this if product collections are used for any custom functionality.