That is a PW-1.
The most recent firmware is 5.6.1.1, there is no 5.6.5 firmware for the PW-1.
The jb version that is on the device now will probably survive but it would not hurt to install the most recent (K5) version from:
https://www.mobileread.com/forums/sho...d.php?t=225030
After installing the Amazon update to 5.6.1.1 you will have to use KUAL and its extension MrPI to install packages.
DO NOT do a 'factory reset' just yet - I am pretty sure there is a way to over-ride the parental controls password.
I can not recall what it is at the moment, so . . . .
Use the advanced search here to find it -
or, search Amazon's forum -
or, check the directions (Kindle User's Guide - it should be on-line somewhere) -
or, wait a bit for someone who knows to post the answer here.