Manual:$wgPasswordDefault/cs

Details
Default password type to use when hashing user passwords. A and B are considered insecure by modern standards. PBKDF2 and bcrypt are considered to be of moderate security level and Argon2 is the most secure value of currently supported options. After changing this setting, users will have their password updated to the new format on next login.

Changing the default

 * 1) Check the "DefaultSettings.php" file in the   directory for the available and preset password encryption types. (As of MW 1.33: ,  ,  ,  ,  ,  ,  )
 * 2) Add   with the parameter to the "LocalSettings.php" file in case you want to change the encryption, e.g. to restore the old MD5 hashing:
 * 3) In order for the password to be saved in a new format, one login from each user has to be done. This way the database is updated.  Alternatively you can use the  maintenance script to convert the hashing algorithm of all passwords without waiting for users to log in. Note that this script only works for ,.
 * 4) Check in the MySQL-database whether the new format has been applied to the fields.