You could try a symlink to the libmyth file you have. I think the standard myth install in arch(manjaro) is version 29.0 now so if you have /usr /lib/libmythtv-29.0.so you can try
Code:
ln -s /usr/lib/libmythtv<yournewversion>.so /usr/lib/libmythtv-0.27.so.0
That may work but I haven't tried it.