I tested the new V61 firmware today and I am a little bit confused what it is good for.
The new firmware does not support ExFat anymore. Means if you format your sd card using the App, it will be formatted in Fat32. And if you sd card is in Exfat (from the older version), you have to re-format the card to make the K2 work with it. On the positive site, this solves the update issue, caused by ExFat. Remember? The Bootloader cannot read Exfat and you have to re-format your card in Fat32 (or use another one) to flash the firmware.
But on the negative site, USB transfer does not work anymore if the sd card is bigger than 32 GB.
Could you please give us some infos what has changed in V61? Any bugs fixed?