Only one license is required for an HA pair. The warm spare unit does not require a separate license. Alerts for warm spare failover can be configured on the Network-wide > Configure > Alerts page. Note: The spare MX must be the same MX model as the primary. Warm spare functionality is not supported between different MX models (for example, MX85 and MX105). https://documentation.meraki.com/MX/Deployment_Guides/MX_Warm_Spare_-_High_Availability_Pair ... View more