Short info: I was not able to install v1.3-3 on my OPX. That was because I could not get the qt5-qtwebsockets from the jolla repos:
I think this is due to old version of SFOS on my phone (2.1.0.11).
So I had to find a version which would work with rockpool.
I tested every version on openrepos and finally found one:
https://openrepos.net/content/aa13q/qt5-qtwebsockets

If you need help, feel free to contact me or ask in this thread.