Differential upper limits calculated from MAGIC observations from the two individual observations periods in 2011 (blue stars for February–April upper limits, red filled triangles for June upper limits). Previous MAGIC-I observations are also shown (Aleksić et al. 2011b): the 2006 discovery (grey circles), 2007 detection (grey squares), and the upper limits derived from the 2009 observations (grey open down-pointing triangles). All observations are corrected for EBL absorption using Domínguez et al. (2011).