  We provide an update on the ongoing monitoring and study of the
highly-relativistic double neutron star binary system PSR J1757-1854, a 21.5-ms
pulsar in a highly eccentric, 4.4-hour orbit. The extreme nature of this
pulsar's orbit allows it to probe a parameter space largely unexplored by other
relativistic binary pulsars. For example, it displays one of the highest
gravitational wave (GW) luminosities of any known binary pulsar, as well as the
highest rate or orbital decay due to GW damping. PSR J1757-1854 is also notable
in that it is an excellent candidate for exploring new tests of General
Relativity and other gravitational theories, with possible measurements of both
Lense-Thirring precession and relativistic orbital deformation (through the
post-Keplerian parameter $\delta_\theta$) anticipated within the next 3-5
years.
  Here we present a summary of the latest interim results from the ongoing
monitoring of this pulsar as part of an international, multi-telescope
campaign. This includes an update of the pulsar's long-term timing and
post-Keplerian parameters, new constraints on the pulsar's proper motion and
corresponding Shklovskii kinematic correction, and new limits on the pulsar's
geodetic precession as determined by monitoring for secular changes in the
pulse profile. We also highlight prospects for future work, including an
updated timeline on new relativistic tests following the introduction of
MeerKAT observations.
