Before this update, different versions of Microsoft SQL Server used different Showplan XML Schemas. Starting with this update, all earlier versions of the Showplan XML Schema are replaced with this latest version. From now on, a single version of the current Showplan XML Schema will be maintained.
Be aware that any new Showplan XML extensions in newer versions of SQL Server are optional elements. This does not mean that earlier versions of SQL Server, such as SQL Server 2012 Service Pack 4 , SQL Server 2014 Service Pack 3 and SQL Server 2016 Service Pack 2, will support all elements that are introduced in a new schema. Those older versions won't generate the optional elements that they don't support. However, the new schema will remain valid for the Showplan XML that is generated by earlier versions.
Different versions of SQL Server will continue producing a separate set of elements in Showplan XML. However, the Unified Showplan Schema is backward-compatible.