What do the suffixes “_v1”, “_v2”, or “_h” in variable names mean?

The SOEP Core Companion contains a detailed description of the versioning and harmonization of variables: Versioning and Harmonization

In SOEP-IS there is the additional aspect that the versions of SOEP-Core are adopted as accurately as possible. This ensures that the variables can be used across studies without encountering the problem of different versions. But it can also mean that only one version of a variable exists in the SOEP-IS. This does not necessarily have to be the “v1” of a variable. If, for example, only the “v3” of a variable is used in the SOEP-IS, then only this “v3” exists in the SOEP-IS data. The harmonized variable may then be identical to this variable. However, the labels of the variables are adapted to the IS replication. This means that the actual years in which a version exists in the IS are written into the variable label, independently of the Core label. This ensures that the data can be used independently of each other.