Evolution of the relativistic electron spectra in the innermost ≤300 kpc of our cluster in the run E model and including all loss and gain terms, using the rescaled magnetic field as in the main text (solid lines) or the original magnetic field produced by the MHD simulation (dashed lines). The different colours mark 10 different epochs, roughly equally spaced in time, from z = 0.5 (black) to z = 0.1 (red).