The latest system jailbreak development progress?

[DINA51]

The following is Google translation, please forgive me if there is any ambiguity
----------------------
I am from China and my device is KO3
First off, I've never been interested in piracy, the Amazon e-book store is convenient and cheap. It's a pity that the KINDLE system made by Amazon is very, very bad! I try not to upgrade it.
But I was still framed twice by Amazon's upgrade method!
For the first time, it was forced to upgrade to 5.12.3, and finally remained at 5.14.2. For this, I complained to the headquarters, but to no avail. Just a few months ago, my KO3 was quietly updated by Amazon to the super hard-to-use 5.14.3, and just fixed the last system version that can be jailbroken. I am angry!
----------------------
Therefore, now I just want to downgrade the system by jailbreaking and return to the previous system.
Your work is my only hope. Hope to crack the code of KINDLE as soon as possible, and give ordinary users a chance to downgrade the system.

Thank you very much, I will always look forward to it, and I wish you all the best of luck!