Under android, I have to kill the app completely from memory after upgrading the firmware. If not, the App means the mooshimeter is still in bootloader mode.
Regarding the timestamp, unix time (seconds since epoch) is a very compatible format and can easily converted in any other date/time format. There are many of date/time formats (with different time zones, daylight saving, etc.), I don’t believe that it’s possible to include them in the mooshimeter firmware. Maybe it’s possible to use the app for reformat when downloading, but this will not help users which use the sd card directly.