SCP should take this new authentication method into account, namely give the possibility in the MySQL server configuration to indicate the PHP script used for signon in phpMyAdmin.

If this file is called, for example, "signon.php", the SCP does not know that it exists and will try to pass the parameters to "index.php", which end up being lost when phpMyAdmin forwards it to "signon.php".

I managed to get around this changing the default docs in IIS website so that signon.php is first and then index.php

you still can use the newest PHPMyAdmin, but you need to configure the „SignOn“ method and create a custom SignOnScript for getting the POST variables: https://docs.phpmyadmin.net/en/latest/setup.html#signon-authentication-mode

There is also a signon.php sample script available there.

Passing the POST variables directly to the default login screen of PHPMyAdmin isn’t supported anymore, as you mentioned, but the SignOn script will do the same job.

Best regards

Bogdan

phpMyAdmin stopped supporting the POST method several years ago, which prevents us from updating it.
Too much time has passed for us to be comfortable using deprecated versions.

Do you recommend any alternative? Maybe Adminer?
In this case, which Database Browser Logon Parameters must be defined in SolidCP.