  The MAGIC telescopes are two Imaging Atmospheric Cherenkov Telescopes (IACTs)
located on the Canary island of La Palma. With 17m diameter mirror dishes and
ultra-fast electronics, they provide an energy threshold as low as 50 GeV for
observations at low zenith angles. The first MAGIC telescope was taken in
operation in 2004 whereas the second one joined in 2009. In 2011 we started a
major upgrade program to improve and to unify the stereoscopic system of the
two similar but at that time different telescopes. Here we report on the
upgrade of the readout electronics and digital trigger of the two telescopes,
the upgrade of the camera of the MAGIC I telescope as well as the commissioning
of the system after this major upgrade.
