Prediction of Astrometric-Microlensing Events from Gaia eDR3 Proper
  Motions
  Astrometric microlensing is a unique tool to measure stellar masses. It
allows us to determine the mass of the lensing star with an accuracy of a few
per cent. In this paper, we update, extend, and refine our predictions of
astrometric-microlensing events based on Gaia's early Data release 3 (eDR3). We
selected about 500.000 high-proper-motion stars from Gaia eDR3 with
$\mu_{tot}>100\,\mathrm{mas/yr}$ and searched for background sources close to
their paths. We applied various selection criteria and cuts in order to exclude
spurious sources and co-moving stars. By forecasting the future positions of
lens and source we determined epoch of and angular separation at closest
approach, and determined an expected positional shift and magnification. Using
Gaia~eDR3, we predict 1758 new microlensing events with expected shifts larger
than 0.1 mas between the epochs J2010.5 and mid J2066.0. Further we provide
more precise information on the angular separation at closest approach for 3084
previously predicted events. This helps to select better targets for
observations, especially for events which occur within the next decade. Our
search lead to the new prediction of an interesting astrometric-microlensing
event by the white dwarf Gaia eDR3-4053455379420641152. In 2025 it will pass by
a $G=20.25\,\mathrm{mag}$ star, which will lead to a positional shift of the
major image of $\delta\theta_{+}=1.2^{+2.0}_{-0.5}\,\mathrm{mas}$.
  Since the background source is only $\Delta G=2.45\,\mathrm{mag}$ fainter
than the lens, also the shift of the combined center of light will be
measurable, especially using a near infrared filter, where the background star
is brighter than the lens $\Delta Ks=-1.1\,\mathrm{mag}$
