Whether DWM1001 supports 850 and 110 Kbps data rate? and when will the firmware available in site?

The DWM1001 supports the 6.8MBps data rate, CH5 only.

I will update the Forum when the DWM1001 docs are released - via Forum Announcement section.

Is the limitation of the DWM1001 due to hardware or software?
If we would need to use the other data rates, then what are the options?

I think is due to the antenna built in DWM1001.

The DWM1001 antenna is optimised for channel 5, but it can also work on other channels…
The on-board FW that comes with DWM1001 only supports the 6.81 data rate and 64 PRF … this is the configuration used in DRTLS.
However users can erase the supplied FW and download own FW into the Nordic and configure the DW1000 to any other configuration they wish/DW1000 supports.