Achievements negative unlock date

[turricanLive]

Hi, I've noticed that when retrieving a game achievements sometimes the unlock date is a negative number. Example:
https://www.xboxleaders.com/api/2.0/achievements.json?gamertag=Turrican&gameid=1480657549

[djekl]

I recieve the exact same numbers on my api.
https://xboxapi.com/dev/achievements/1480657549/Turrican

It seems that its an achievement unlocked offline. Will need to include that in this one here to help.

[turricanLive]

Do you know if there a way to derive the actual date from this negative number?

[djekl]

Achievements unlocked offline don't have a date associated with them. I am assuming here but I know a unix timestamp at 0 is 1970, this negative time is probably 000-00-00 00:00:00

[jasonclemons]

That timestamp translates to Tue, 20 Apr 1948 07:18:00 GMT. I'm sure it's zero hour for the way Microsoft does their timestamps.

I will leave it the way it is now, but I have added an unlockedoffline key to designate achievements unlocked offline.