Full Length Filenames on the SD Card

@andrivet When I look at the SD card with ADVi3 I can see the full length name stored on the card by my computer. However when OctoPrint retrieves the file names using the Marlin M20 command only the 8.3 format of the names are sent.
Is there another command in ADVi3 that OctoPrint could use that will return the full length filenames from the SD card?

Yes and this is the normal behavior of Marlin, see:

List the entire contents of the SD card to serial output in the more compact DOS 8.3 format.

M33 - Get Long Path

Thanks for the quick reply.
I tried the M33 command from the OctoPrint terminal And I received “unknown command M33”. I have an MMSP with 4.0.6.

Yes, it is not currently supported by ADVi3++. You need to define LONG_FILENAME_HOST_SUPPORT in Configuration_adv.h and recompile.

Will this command be supported in ADVi3++ 5.0?

Probably, but activation of new features is always dependent of the memory (SRAM) required by it. SRAM is a precious resource.