I still use Kindle DXG pdf for reading A5 and A4 pdf & djvu books and documents as well as comics outdoors during the sunny days, together with Kobo Aura One that I also use indoors.
You must install KPV reader thereon though, because without KPV viewer DX doesn't have half the necessary pdf reading functions, can't read epubs and is slower.
Jailbreaking and installing KPV takes just a few minutes after you collect all the necessary files, you just transfer the files to DX and restart it few times.
https://www.mobileread.com/forums/sh...ght=kpv+viewer
https://www.mobileread.com/forums/sh...ght=kpv+viewer