It seems someone has submited similar request.
I am in great hoping that a config file can be added to mupdf, and it can be used to change the increasements of 'h', 'j', 'k' and 'l', allow continous scrolling of pages and antomatic reload file(this would be useful in tex file edit).
It may be some kind of outside the aim of mupdf, but I think this can greatly improve its practicability.
Thanks a lot!
*** This bug has been marked as a duplicate of bug 691330 ***