After the firmware update to version V1 R4.6.2 HFA 201122, it is necessary to adjust the time configuration of the devices.
After the firmware update to version V1 R5.4.3 this changed registry keys are no longer necessary and can be deleted. Instead the standard SwyxWare are be used again.
After initial commissioning or a factory reset, the time source is set to "System".
This must be changed to "SNTP".
Affected phones: L62, L64, L66
This setting can also be set globally by the following registry key.
Also this setting has to be applied:
sntp-tz-offset = 60
A restart of the Phonemgr service is necessary so in order for the settings to be correctly provisioned to the phones.