Manual:$wgPasswordDefault

Details
Default password type to use when hashing user passwords.

How to use it
Check the   in the   folder for the available and preset password encryption types. Add   with the parameter to the   in case you want to change the encryption Example : 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. Check the MySQL-database whether the new format has been applied to the fields. Example :

You can execute  to convert the hashing algorithm of all passwords without waiting for users to log in.