From 1 June, 2023 Microsoft Defender for IoT is licensed via site licences for organisations protecting their Operational Technology  (OT) environments.

These site licences are applied to a site which is a physical location such as an office building, hospital, rig etc. There are different tiers depending on how many devices need to be protected, starting at an Extra Small tier for up to 100 devices, Small for up to 250 devices, Medium for up to 500, Large for up to 1,000, and an Extra Large tier for up to 5,000 devices.

Customers self-serving buy these site licences through the Microsoft 365 Admin portal and then add them to an Azure Subscription in the Azure Management Portal.

Find the announcement here: https://bit.ly/3OmX52M, and information on how to purchase and manage the licences here: https://bit.ly/45lpvkx.