There’s now a v1.10 manual on the website. As Scott mentioned, the feature additions are fairly minor, but they’ve been documented, and the Voltages Mode ‘pict-o-cheat’ graphic has been updated accordingly.
Invalid DFU suffix signature
A valid DFU suffix will be required in a future dfu-util release!!!
Cannot open DFU device 0483:df11
No DFU capable USB device available
Got this error because the SMT32 Bootloader driver installed automatically. If this happens, you can check “list all devices” under Zadig options to see SMT32 in the list and replace the driver.