Please download the update files for older versions from the links below.
<Firmware>
Version 17.27
Version 17.29
Version 17.30
Version 17.32
Version 17.34
Version 17.37
<FPGA>
Version 28.60
Version 28.63
Version 28.70
Version 28.81
Version 28.82
Version 28.86
Version 28.87
The firmware and FPGA downgrade procedures are the same as for updates.
For detailed instructions, please refer to step 5 in the FAQ linked below.