data-konzept

'Customer planning for migration to SQL Server 2016 asked for clarification on running mixed version of SQL Servers in their Replication Topology.  I searched for “mixed version”, but was unable to find our posted topic. My colleague George Mason tracked it down under “upgrade”.  I’m posting key paragraph along with quick reference examples.

Upgrade Replicated Databases
https://msdn.microsoft.com/en-us/library/ms143699.aspx

SQL Server 2016 supports upgrading replicated databases from previous versions of SQL Server; it is not required to stop activity at other nodes while a node is being upgraded. Ensure that you adhere to the rules regarding which versions are supported in a topology:

• A Distributor can be any version as long as it is greater than or equal to the Publisher version (in many cases the Distributor is the same instance as the Publisher).

• A Publisher can be any version as long as it less than or equal to the Distributor version.

• Subscriber version depends on the type of publication:

  • A Subscriber to a transactional publication can be any version within two versions of the Publisher version. For example: a SQL Server 2012 Publisher can have SQL Server 2014 and SQL Server 2016 Subscribers; and a SQL Server 2016 Publisher can have SQL Server 2014 and SQL Server 2012 Subscribers.

Key point Publisher is within 2 builds of the Subscriber and the Distributor is same or higher build then Publisher. 

These are supported:

• Publisher (2008/R2)  -> Distributor (2016) -> Subscriber (2012)

• Publisher (2014)  -> Distributor (2016) -> Subscriber (2008/R2)

• Publisher (2016)  -> Distributor (2016) -> Subscriber (2012)

Not supported:

• Publisher (2016)  -> Distributor (2016) -> Subscriber (2008/R2)

• Publisher (2008/R2)  -> Distributor (2016) -> Subscriber (2016)

In chart above SQL Server 2008/R2 means either SQL Server 2008 or SQL Server 2008R2.  For all versions, ensure you’re running on most recent SQL Server service pack to take advantage of software fixes and enhancements.  Check out Microsoft Release Services blog for updates on service packs and cumulative updates.'...

https://blogs.msdn.microsoft.com/repltalk/2016/08/12/suppported-sql-server-versions-in-replication-topology/