What are the SYNC_SEND and SYNC_RECEIVE versions in the versions table?

Answer

Note:
This article pertains to ArcGIS versions 9.x and 10. Later versions of ArcGIS may contain different functionality, as well as different names and locations for menus, commands and geoprocessing tools.

Note:
ArcSDE software, including the application server, command tools, and SDK with C and Java APIs, was deprecated at ArcGIS 10.2.2 and is no longer distributed. ArcGIS software features were deprecated, rather than immediately removed, to provide customers with backward compatibility and give as much advance notice as possible to adopt newer technology.

In geodatabase replication, on a successful synchronization between primary and secondary replicas, SYNC_RECEIVE and SYNC_SEND versions are recorded in the sde versions table. These temporary versions are managed by ArcSDE and should not be manually deleted from the table. They are deleted when the replica is unregistered by way of the Replica Manager dialog box in ArcCatalog or ArcMap.