Point in time (Unix timestamp) when the user changed name last time; 0 if unknown.
Point in time (Unix timestamp) when the user changed photo last time; 0 if unknown.
A two-letter ISO 3166-1 alpha-2 country code based on the phone number of the user; may be empty if unknown.
Month when the user was registered in Telegram; 0-12; may be 0 if unknown.
Year when the user was registered in Telegram; 0-9999; may be 0 if unknown.
Contains basic information about another user that started a chat with the current user.