#1- I think this is part of default Roundcube.
#2- Password plugin is bundled with default Roundcube. Just configure and activate it.
1. Configuration ---------------- Copy config.inc.php.dist to config.inc.php and set the options as described within the file.
#1- Which version do you use?
#2- To activate a plugin: ...$rcmail_config['plugins'] = array( "password", "anotherplugin", "andanotherplugin");
Could not save new password