What client and ArcSDE geodatabases for SQL Server Express versions are compatible?

Because connections to the geodatabases on database servers are always direct connections, you must have a direct-connect driver on your client application that is the same version as the geodatabase.

ArcGIS Desktop, ArcGIS Engine, and ArcGIS Server Workgroup at release 10 include backward-compatible direct-connect drivers so you can make direct connections from these clients to geodatabases that are at the 9.2 or 9.3 release.

There are also direct-connect drivers you can install separately to make direct connections in the following mixed-release configurations:

It is important to note that it is the drivers in the connecting client that determine the version of the geodatabase that gets created. If you have a mix of client releases at your organization, there is the potential to have different release geodatabases on the same database server.

The following scenarios are possible when using mixed client releases with database servers:

See Direct connect compatibility between clients and ArcSDE geodatabases for general rules on interoperable connections to ArcSDE geodatabases. When reading this topic, keep in mind that database servers were introduced with the 9.2 release and that you cannot use an ArcSDE service to connect to geodatabases on a database server.