Official statement from dr. wurzer:
Dear Community,
Some media have written about malware on devices from our supplier Gigaset. We have of course followed up on these reports and assessed the situation with our supplier.
The Volla Phone is not affected for several reasons:
1. Only older models from Gigaset are affected.
2. it is not a hardware (chipset) security vulnerability
3. The Volla Phone uses a different operating system with a different code base.
4. The Volla Phone uses a standalone, independent OTA server.
Thank you for the attentive users who brought the case to our attention.
Source: Volla User Community on Telegram