The Kobo Aura HD's replacement is NOT the Kobo Aura (2nd edition) or even the Kobo Aura One (which has an even larger screen), but rather the 6.8" Kobo Aura H2O; it has the same screen resolution and feature set as the Kobo Aura HD, but is also waterproof.
https://ca.kobobooks.com/products/kobo-aura-h2o
All best wishes.