Firmware downgrade on newest kindle devices?

[Spring1898]

I decided to pick up a couple kindles on the prime big deal event, and then read that the new DRM firmware obfuscates all the kindle files. I imagine that at some point an update to allow for using the serial to help find the files, but until then I have a couple questions:

It looks like there is a new way to jailbreak at least the 12th gen and colorsoft. If the new kindles do come with the latest firmware, which I suspect they will, is it possible to downgrade the 5.18 series of firmware after jail breaking?

From what I understand up to 5.18.4 still allows the files to be seen. But I have not seen too many people discussing downgrading to this firmware from the latest.