UTC?
unixtime, epochtime whatever you want to call it is not necessarily UTC - it's a representation of the system clock in seconds so it will go on whatever the system clock is set to.
It can be UTC but I bet most such affected systems in Oz will stumble before those in Europe - because of the time difference. saying that it all goes belly up at xx:xx:xx UTC means the clocks in Oz must have some ephemeral immunity for that half day... probably more effort than the fix
jus' sayin'