Hello, everybody! I have just bought Arcor twintel phone with the firmware version 3.99a. According to the Arcor site, 3.99c is the latest, while Pirelli version is 3.99d. Could anyone please summarise briefly the difference between these three firmware versions? After searching the forum I've got an impression that the main difference between c and d is due to different langpacks and multiple sip profiles available in d versus only one in c. Is it true? Anything else worth mentioning? What is the difference between a and c? How safe is the firmware update process? If something goes wrong, is there any way to recover the device which does not start? Thanks in advance!