Creator Pro compatability with Flashprint 5

I have a Creator Pro - not a 2 or a 3, the original. Perforce, I print exclusively from SD card.
I upgraded from Flashprint 3 to Flashprint 5 recently and discovered that V5 produces print files with the extension '.gx' and my printer doesn't even detect such files on the SD card.
I processed the same '.stl' file using V3 which produced the usual 'x3g' file which the printer duly recognised and printed.

Attached is a photo of the ROM details displayed at startup.
Attachment 18711

I have been unable to find any sign of firmware upgrades for the printer, nor of any program which can convert '.gx' files to '.x3g' format on flashforge's web site.

Any help would be greatly appreciated.
Peter.