Amazon upgraded everything and added waterproofing.

Amazon’s All-new Kindle Paperwhite comes along just in time. While we’ve loved prior versions, the e-reader hasn’t changed much since its debut in 2012, aside from incremental upgrades such as better front-lighting, additional storage and a few software tweaks. Its most recent version, from 2015, was losing ground to similarly priced competitors such as the Kobo Clara HD.
…
Read full post here:
https://www.pcworld.com/article/3326534/consumer-electronics/amazon-all-new-kindle-paperwhite-review-2018.html