  Analyzing single-dish and VLBI radio, as well as \textit{Fermi}-LAT
$\gamma$-ray observations, we explained the three major flares in the
$\gamma$-ray light curve of FSRQ J1048+7143 with the spin--orbit precession of
the dominant mass black hole in a supermassive black hole binary system. Here,
we report on the detection of a fourth $\gamma$-ray flare from J1048+7143,
appearing in the time interval which was predicted in our previous work.
Including this new flare, we constrained the mass ratio into a narrow range of
$0.062<q<0.088$, and consequently we were able to further constrain the
parameters of the hypothetical supermassive binary black hole at the heart of
J1048+7143. We predict the occurrence of the fifth major $\gamma$-ray flare
that would appear only if the jet will still lay close to our line sight. The
fourth major $\gamma$-ray flare also shows the two-subflare structure, further
strengthening our scenario in which the occurrence of the subflares is the
signature of the precession of a spine--sheath jet structure that
quasi-periodically interacts with a proton target, e.g. clouds in the
broad-line region.
