Legacy Rom is a custom rom made for the GPD XD gaming device. When it was first released, the rom system partition was formatted in ext3 format. Now to most of us that is not a problem and from our experience we couldn't care less because changing the format does nothing as far as performance or user interaction. The main reason I reformatted it was to take advantage of the TWRP Recovery. So if you do not want to mess with it, do not worry you can still install CWM. If you do not wish to reformat or upgrade, I ask you to please read on to see how easy it is to update. To know why TWRP is better than CWM you can read about it HERE.
As of September 23rd of 2017 all distrubutions of Legacy Rom from this website will be in ext4 format.
Please read this tutorial to inform you on how easy it is to change versions.