Supplementary release documentation for software v1.68 (SIR 1xx devices)

Address corruption of the settings (e.g. the serial number) in SIR devices. Make a backup important settings (use with care).
A device with corrupted settings will not be able to connect to or be identified on the provisioning platform, resulting in audio not being played or not being updated. In addition to the software improvements in release v1.68 aimed at addressing the corruption issue, Streamit also implemented an option to backup important settings, so that they can be recovered in case corruption was to occur.