This is a simple plugin for wordpress / woocommerce, that allows administrators to declare products as out of stock, regardless of their actual stock status. Possible use-cases are seasonal items, old products, etc.
I will not go into depths on how to install wordpress plugins as there is a bunch of directions for it over the internet. But generally there are 2 easy solutions.
A) In the wordpress administrator area, click Plugins->Add new, click on the “Upload Plugin” button, then simply upload the plugin zip.
B) Simply put the unzipped version of the plugin into your code repository under the folder “wp-content/plugins”
Then simply activate the plugin from the Plugins menu in the administrator area.
You will find the menu under Woocommerce Tab in the backend. Click Woocommerce-> Out of Stock to open the configuration area.
There you will find two lists, the first is a list with all available store tags and the other is all the available product categories.
Keep in mind to make changes you will have to Ctrl+Click (Windows, Linux) or CMD+Click (Mac), to either select or unselect a certain category. The reason is that the lists are multiselect elements, thus simple click will unselect the previous choices.
To save simply click the “Save Changes” button.
You can find it here.