If anyone is looking for the answer, I can confirm that JailBreak survives updating to 5.13.5. I'm still on 5.13.3, but my mother's Paperwhite 3 got updated to 5.13.5 through OTA. She wanted Screensaver Hack back so badly (because native Kindle cover screensaver mode doesn't work for 90% ebooks), so I tried to revive JailBreak. What I did was
https://www.mobileread.com/forums/sh...3&postcount=26 (thank you, NiLuJe!). I had to reboot Kindle, as running ;log r did nothing in my case. Then, I installed JB Hotfix using ;log mrpi (because updating through UYK didn't work out for me).