such a great and essential application, many thanks to th developers for all their work! I gleaned that okular is currently being ported to qt5, is there any chance of update or progress with this and any other features/bugfixes for the upcoming release? also would it be portable to other non linux environments?

Since KDE Applications 16.12 there is a KF5 / Qt5 based Okular, which got version 1.0 for that occasion.

Regarding portability, a lot of KDE's Applications can be built on Windows (using "craft") as well as Mac. KDE's continuous integration system also builds Okular on Windows. Not sure how well it works from a user's perspective at the moment, though.