Update: 99.99% uptime for all Azure Service Bus Premium namespaces in Availability Zone regions

Starting May 1, 2026, all Azure Service Bus [Premium namespaces](https://learn.microsoft.com/en-us/azure/service-bus-messaging/service-bus-premium-messaging) deployed in regions with [Availability Zone](https://learn.microsoft.com/en-us/azure/reliability/availability-zones-overview) support now qualify for a 99.99% uptime [SLA](https://www.microsoft.com/licensing/docs/view/Service-Level-Agreements-SLA-for-Online-Services?lang=1). Premium is the tier customers choose for their most important workloads, and this update brings the SLA in line with the zone-redundant infrastructure those namespaces already run on. Previously, the 99.99% SLA required partitioned namespaces to be enabled. That requirement has been removed - any Premium namespace in an AZ region now receives the higher SLA automatically. Availability Zones are physically separate datacenters within an Azure region, each with independent power, cooling, and networking. A Premium namespace deployed in an AZ region is automatically replicated across multiple zones, so the messaging service stays available even if a full datacenter goes offline. No configuration changes are required for existing deployments to benefit from the higher SLA. Partitioned namespaces remain fully supported for workloads that need higher throughput through multi-broker distribution. The change is purely about SLA eligibility - partitioning is no longer a prerequisite for the 99.99% commitment. Learn more: * [SLA for Azure Service Bus](https://www.microsoft.com/licensing/docs/view/Service-Level-Agreements-SLA-for-Online-Services?lang=1) * [Service Bus Premium tier documentation](https://learn.microsoft.com/en-us/azure/service-bus-messaging/service-bus-premium-messaging). * [Azure Service Bus blog](https://techcommunity.microsoft.com/blog/messagingonazureblog/azure-service-bus-premium-now-offers-99-99-sla-in-all-availability-zone-regions/4517933)