  Very high energy gamma ray emission from the active galactic nucleus PG
1553+113 was observed during 2005 and 2006 by the MAGIC collaboration, for a
total observation time of 18.8 hours. Here we present the results of follow up
observations: more than 20 hours of good quality data collected by the MAGIC
Telescope during the 2007 and 2008 campaigns. The obtained spectra are compared
and combined with previous measurements, and corrected for absorption adopting
different EBL models. Upper limits on the unknown source redshift are derived
by assuming the absence of a break in the intrinsic spectrum, or alternatively
by constraining the hardness of the intrinsic source spectrum.
