Prior to Json.NET 4.5 dates were written using the Microsoft format: "/Date(1198908717056)/". If your server sends date in this format you can use the below code to serialize it to NSDate:
(NSDate*) getDateFromJSON:(NSString *)dateString
{
// Expect date in this format "/Date(1268123281843)/"
int startPos = [dateString rangeOfString:@"("].location+1;
int endPos = [dateString rangeOfString:@")"].location;
NSRange range = NSMakeRange(startPos,endPos-startPos);
unsigned long long milliseconds = [[dateString substringWithRange:range] longLongValue];
NSLog(@"%llu",milliseconds);
NSTimeInterval interval = milliseconds/1000;
NSDate *date = [NSDate dateWithTimeIntervalSince1970:interval];
// add code for date formatter if need NSDate in specific format.
return date;
}