Correct time zone in EVSE data records regarding day light saving?

[ahzf]

In OICP v2.3 there is a mandatory property "timezone" of EVSE data records having a format like "UTC+01:00". But for EVSEs in Germany what is the correct time zone regarding day light saving? Because half a year it is "UTC+01:00" and the other half "UTC+02:00", or?