11.1 Scope
The scope of this section is to define both best practices and mandatory behaviour for specific aspects of transformation between different versions of SDMX.
11.2 Compatibility and new DSD features
The following table provides an overview of the backwards compatibility between SDMX 3.0 and 2.1.
| SDMX 3.0 feature | SDMX 2.1 compatibility | Comments |
| Multiple Measures | Create a Measure Dimension | For a Measure |
| Arrays for values | Cannot be supported | Arrays are always reported in a verbose format, even if one value is reported |
Relationship | Can be ignored, as it does not affect dataset format | |
| Metadata Attributes | Can be created as Data Attributes | Not for extended facets |
| Multilingual Components | Cannot be supported | |
| No Measure | Can only be emulated by ignoring the Primary Measure value | |
| Use extended Codelist | A new Codelist with all Codes must be created | |
| Sentinel values | Cannot be supported in the DSD | Rules may be supported outside the DSD, in bilateral agreements |
The following table illustrates forward compatibility issues from SDMX 2.1 to 3.0.
| SDMX 2.1 feature | SDMX 3.0 compatibility | Comments |
| Measure Dimension | ||
| Primary Measure | Create one Measure with role ‘PRIMARY’; use id=”OBS_VALUE” |