Check you version of Roundcube
Go to: https://myroundcube.com/myroundcube-plugins/plugin-manager
Download the plugin manager version for your roundcube
Extract and upload the the roundcube plugins directory
Upload to
# /usr/share/psa-roundcube/plugins
Modify the config file
# /usr/share/psa-roundcube/config/config.inc.php
$config['plugins'] = array('password', 'markasjunk2', 'sieverules');
Change to
# $config['plugins'] = array('plugin_manager', 'password', 'sieverules');
Access Roundcube and login. Click About
This should pop up
Add the file to roundcube
# touch /usr/share/psa-roundcube/urv58kf60qjia0n1h447mr8i12.myrc
Go to Settings > You Should now see the Plugins Manager