Now Maximum of 10 alternate keys can be defined for an entity/table – 2021 Release Wave 1 – Dynamics 365

Previously, a maximum of 5 alternate keys could be defined for an entity.

https://docs.microsoft.com/en-us/dynamics365/customerengagement/on-premises/developer/define-alternate-keys-entity#create-alternate-keys

With 2021 Release Wave 1, the limit has been increased to 10.

https://docs.microsoft.com/en-us/power-platform-release-plan/2021wave1/data-platform/increased-alternate-key-limits

While trying to create the 11^th key we will get the below error message as shown below

The table could not be updated: Maximum 10 EntityKeys are supported per Entity.

Check other posts on 2021 Release Wave 1  –

Blog posts on 2021 Release Wave 1 – Dynamics 365

Hope it helps..