FYI regarding my working WinterBreak on Kindle PW5 (11th FW 5.17.1) with KOReader.
1. Followed
https://kindlemodding.org/jailbreaking
2. Installed
https://build.koreader.rocks/downloa...2025-01-07.zip
3. Modified the "Update Channel" to "Development", then updated KOReader successfully.