Download desired firmware build from Amazon's servers:
Code:
https://s3.amazonaws.com/firmwaredownloads/update_kindle_all_new_paperwhite_11th_5.14.1.1.bin
https://s3.amazonaws.com/firmwaredownloads/update_kindle_all_new_paperwhite_11th_5.14.2.bin
https://s3.amazonaws.com/firmwaredownloads/update_kindle_all_new_paperwhite_11th_5.14.3.bin
My suggestion is to first manually update your PW5 to 5.14.1.1 and have a change to see how the new UI looks like. Since 5.14.1.1 still includes older UI code and in case you dislike it you at least have a choice to revert to that older UI (that you probably have on 5.14.0.1.) after jailbreaking.
If you like the new UI changes then you can then update your device to 5.14.3 (after successfully jailbreaking it while on 5.14.1.1 or 5.14.2).
I'm in the dislike camp and don't plan to update my PW5 from 5.14.1.1. If it wasn't necessary for successful jailbreaking I wouldn't even update it from 5.14.0.1