Azure Service Bus Messaging is one of the most powerful message brokers available in public cloud infrastructure today and it processes nearly 500 Billion message transactions per month. Microsoft also belives that Azure Service Bus, delivered from the nearest Azure datacenter over redundant network connectivity, is a choice far superior in terms of cost and reliability to most on-premises messaging cluster installations, even if the core workloads run and remain in an on-premises environment.
Considering their future strategy around messaging, analysis of market and community needs, Microsoft yesterday announced that they will not provide an immediate successor for the standalone Service Bus for Windows Server 1.1 product. Service Bus for Windows Server 1.1 was originally shipped as a free download inside Azure Pack. It will go out of mainstream support on January 9, 2018, following the regular Microsoft lifecycle policy. Microsoft also clearly mentioned in their blog that they will no longer deliver a Windows Server or Windows Client installable message broker outside of that context.
Read more about this announcement here.