Release 4.0 introduces the new namespace concept which supports prefixes and longer names for objects in the R/3 System. In the IDoc interface, this affects IDocs), which are stored in database tables. As a result, a database conversion is required for the IDoc table which contains IDocs from Releases 2.1-3.0B.
To reduce the time required for the conversion, SAP recommends that all archivable IDocs are archived before the conversion. This applies to all systems which use IDocs from Releases 2.1-3.0.
Different strategies can be implemented, according to the release used as a basis for the conversion to 4.0:
The corresponding IDoc table is only converted during 4.0 production operation. You can define exception times, during which no conversion can take place (incremental conversion to minimize the disruption to production operation). The database conversion must be complete before the next upgrade (from 4.0 to a subsequent release).
To discover more about incremental database conversions, you should read Customizing information.
For more information about archiving, you should read the documentation in the R/3 Library ( CA -> Intermediate Document Interface -> The IDoc Interface -> Reference Manual -> Archiving IDocs ) where you can also learn more about displaying or changing the archive status in the standard system.