A WeChat friend hasn't updated for a long time and hasn't replied to the message. How can I contact him?

You can look at his micro signal or the name of WeChat. Generally, people who play early use QQ account number and name, and then check his QQ number accordingly.

Wechat nickname, reverse check QQ number

If you know the name, you can use Friends Network or Renren Network to inquire.

For the above three kinds, filling in more information in the search will help you eliminate interference, such as gender, age, hometown, place of residence and so on.