Restores the previous firmware (e.g. issues after an update).
Caution:The PBX reboots automatically after you restore the previously used firmware. This interrupts all the connections with/to the web server, all the calls and the data services. Unsaved data is lost!
Note: The previous firmware will only be retained in the flash memory for four weeks. After four weeks, the previous firmware will be overwritten by the current firmware to prevent the restoration of obsolete data.