Squirrelmail change password plugin doesn’t work. How to fix it?

SquirrelMail is a standards-based webmail package written in PHP. It includes built-in pure PHP support for the IMAP and SMTP protocols, and all pages render in pure HTML 4.0 (with no JavaScript required) for maximum compatibility across browsers. It has very few requirements and is very easy to configure and install. SquirrelMail has all the functionality you would want from an email client, including strong MIME support, address books, and folder manipulation. (This is from the official page of Squirrelmail project.) And it is a good tool to reach your emails from everywhere, so a lot of people use it. One important plugin in Squirrelmail is Change password. Yes, of course, it is good for everybody to be able to change his password, but sometimes not everything work like we expect. Here we will talk about some problems which can arise with change password plugin.
Could not find Pear DB library, this is one of the errors which you can have after entering your old password, two times your new password and press on submit button. In this case the fix can be very easy. It is possible that you only have to install php-pear and php-db and that is, this will fix the problem. If not, then you will have to dig deeper, but don’t worry, search in internet, there are many other suggestions.
Other error can be Could not make database connection, also after try to change the password. In this case you will have to do a small change in one file of change sclpassword plugin. In Debian Linux and other distributions made on Debian architecture this file is here /usr/share/squirrelmail/plugins/change_sqlpass/config.php there normally you will find this code.

$csp_dsn = 'mysql://db_user:password@localhost/db_name';
Where db_user, password and db_name are your correct database user, password and database name for your mail server. This “mysql” shows the database backend used in PHP or “phptype” how you can see it in other explanations. Here you will have to change “mysql” to “mysqli” if you use MySQL version >= 4.1 or MariaDB. For MySQL version <= 4.0 no need of change. But if you use other kind of database here are the currently supported database backends.
I hope this short topic can be helpful for somebody.