Top panel: photon–photon absorption correction (exp[τ_γγ]) for the source IC 310 at z = 0.0189, based on the EBL model by FR2017. Bottom panel: blue data-points and continuous line were taken during an outburst phase, the red data and continuous line during a prolonged high-state (see text). The 50-h 5σ and 100 h 2σ sensitivity limits for CTA, and the HAWC 5 years limits are shown. The blue dotted line and the red dashed one indicate the SWGO and LHAASO 5 years 5σ limits, respectively.