There’s an updated (January 2019) Dynamics 365 for Operations Server On-Premises licensing guide. If you haven’t seen a recent version of this guide you’ll notice the new look, and there’s a useful section on page 9 detailing the licensing of Retail scenarios – something’s that only been available since late 2018.

As usual you’ll find this guide here: http://bit.ly/MSLicensingGuides.