Left: NAFF distribution of the Kepler-444 system from the model posterior that includes the binary companion BC. The vertical dotted line represents our stability threshold. Any system configuration with a NAFF chaos estimation smaller than −4.2 (right-hand side) is flagged as stable. Middle: mass distributions of planet c, both presenting the full posterior distribution (black line) and the distribution of NAFF-stable configurations only (plain green). Right: same as middle but for planet f.