OK. Now install a visual diff program. Some thing like NotePad++ with the visual diff plug in. Or install the trial version of ExamDiff Pro. Do a comparison of the configuration.h and configuration_adv.h files. You need to move the settings from the osoyoo version of the files over to the new format. (Some option names have changed. Some have been added.) It should only take 10 minute to find the import diff's and move them over to the new file.

Once you have done that... Try building (and loading) the firmware. When you get it going... The printer will be running the current version of Marlin.