  The globular cluster (GC) M15 (NGC 7078) is host to at least eight pulsars
and two low mass X-ray binaries (LMXBs) one of which is also visible in the
radio regime. Here we present the results of a multi-epoch global very long
baseline interferometry (VLBI) campaign aiming at i) measuring the proper
motion of the known compact radio sources, ii) finding and classifying thus far
undetected compact radio sources in the GC, and iii) detecting a signature of
the putative intermediate mass black hole (IMBH) proposed to reside at the core
of M15. We measure the sky motion in right ascension ($\mu_{\alpha}$) and
declination ($\mu_{\delta}$) of the pulsars M15A and M15C and of the LMXB AC211
to be
$(\mu_{\alpha},\,\mu_{\delta})_{\text{M15A}}=(-0.54\pm0.14,\,-4.33\pm0.25)\,$mas$\,$yr$^{-1}$,
$(\mu_{\alpha},\,\mu_{\delta})_{\text{M15C}}=(-0.75\pm0.09,\,-3.52\pm0.13)\,$mas$\,$yr$^{-1}$,
and
$(\mu_{\alpha},\,\mu_{\delta})_{\text{AC211}}=(-0.46\pm0.08,\,-4.31\pm0.20)\,$mas$\,$yr$^{-1}$,
respectively. Based on these measurements we estimate the global proper motion
of M15 to be
$(\mu_{\alpha},\,\mu_{\delta})=(-0.58\pm0.18,\,-4.05\pm0.34)\,$mas$\,$yr$^{-1}$.
We detect two previously known but unclassified compact sources within our
field of view. Our observations indicate that one them is of extragalactic
origin while the other one is a foreground source, quite likely an LMXB. The
double neutron star system M15C became fainter during the observations,
disappeared for one year and is now observable again---an effect possibly
caused by geodetic precession. The LMXB AC211 shows a double lobed structure in
one of the observations indicative of an outburst during this campaign. With
the inclusion of the last two of a total of seven observations we confirm the
upper mass limit for a putative IMBH to be M$_{\bullet}<500$ M$_{\odot}$.
