Six-eight percent (1σ, inner, black), 90% (1.6σ, middle, red), and 99.7% (3σ, outer, green) confidence level contours of the high-energy cut-off energy E_cutoff versus the photon index Γ based on the joint PCA/JEMX/HEXTE/ISGRI spectra of rev. 668, rev. 670 and rev. 674 (the last revolution of INTEGRAL in the rising phase) of IGR J17473–2721. The best-fit value is indicated by a “+”.