mac updater

NSData* data = [NSData dataWithContentsOfFile:pathString];

if (!data)
  return true;

NSError* error = nil;
NSDictionary* info_dict = [NSPropertyListSerialization propertyListWithData:data options:NSPropertyListImmutable format:nil error:&error];

if (!error)
  return true;

NSString* min_version_str = info_dict[@"LSMinimumSystemVersion"];
if (!min_version_str)
   return true;

// etc