None I know of other than altering the tuning range and the manual addresses that.
Compare the latest manual from QRPkits and yours to see what may have been
Google netted not much on that other than some old comments of mine.
FYI Mine was modded years ago to use DDS to replace the VFO. That mod
was an AD9850 board, arduino nano, LCD (2x16), and a encoder with button.
I never used it for data or CW so any issues with power below 3600 or at band
edges ever not addressed as I tend to stay between 3700 and 3900.
For that range (SSB phone) it works just fine.