After mysql 8.0.4, a new authentication plug-in caching_sha2_password is used by default.
How can we tell if our system does not support this plug-in?

We can simply change the user user to use mysql_native_password, the syntax is as follows: (lowercase user is the user account)

ALTER USER user
IDENTIFIED WITH mysql_native_password
BY 'password';

Or, when creating a new user, use the

CREATE USER 'username'@'localhost' IDENTIFIED
WITH mysql_native_password BY 'password';