Sony Picture Entertainment Inc. Hack Update

22 November : Sony computer systems hacked, exposing embarrassing emails and personal details about stars

7 December : North Korea denies accusations that it is behind the cyber-attack, but praises it as a "righteous deed"

16 December : "Guardians of Peace" hacker group threatens 9/11-type attack on cinemas showing film; New York premiere cancelled

17 December : Leading US cinema groups say they will not screen film; Sony cancels Christmas Day release

19 December : FBI concludes North Korea orchestrated hack; President Obama calls Sony cancellation "a mistake"

20 December : North Korea proposes joint inquiry with US into hacks, rejected by the US

22 December : North Korea suffers a severe internet outage; US authorities decline to comment

23 December : Sony bosses appear to change their minds, saying they will now give The Interview a limited Christmas Day release

25 December : The Interview is shown in some US cinemas and released online