Three days ago, NEKO WORKs released the NEKOPARA OVA Extra episode on Steam. The story is a prequel and takes place half a year before the main story. Also, the paid episode will include the bonus Non-Credit Ending Movie. Price is $4.99 or ¥554.11. For more details, check out the store page. Here's a trailer.
Official Website: http://nekoparaova.com/ex/index.html