Topics in the backward compatibility section describe changes in behavior between versions of Microsoft SQL Server replication. It is important to understand backward compatibility if you are upgrading or if you have more than one version of SQL Server in a replication topology.
Deprecated Features in SQL Server Replication
Replication features that have been retained in Microsoft SQL Server 2017 for backward compatibility, but which will be removed in a future version of SQL Server.
Breaking Changes in SQL Server Replication
Replication feature changes that might require changes to applications.