SED fit from UV to hard X-rays of Mrk 110 using the RELAGN+RELXILLCP baseline model for the 2019 (blue) and 2020 (red) simultaneous XMM-Newton and NuSTAR spectra. Left panels: the black-hole spin is allowed to vary, and is found to be greater or equal to 0.997. The values of the best-fit parameters are reported in Table 2. Right panels: the black-hole spin value is fixed to zero. The best-fit parameter values are reported in Table 3. Top panels: data-to-model ratio. Bottom panels: intrinsic SED corrected for Galactic reddening and absorption (solid curves), with the main individual emission components of the baseline model: Outer disc (dotted curves), warm, optically-thick Comptonisation (dashed curves; warm corona), hot, optically-thin Comptonisation (dotted-dashed curves; hot corona), and relativistic reflection (three-dotted-dashed curves).