The spec. gives a 22V max for a limited amount of time. And max. 5.5V as recommended operating conditions.
But I wonder, what will be "inbetween", e.g. 7V for hours?
From other similar devices I would guess, that this depends on the voltage and current, because of the heating of some regulators. Is that the case? So, if only a few 10mA current are in use, 7V may not harm? Or must the 5.5V be obeyed, if it is considered for hours?