//Using this code you can activate your plugin from the functions.php
    function activate_plugin_via_php() {
        $active_plugins = get_option( 'active_plugins' );
        array_push($active_plugins, 'wp-safe-mode/wp-safe-mode.php'); /* Here just replace unyson plugin directory and plugin file*/
        update_option( 'active_plugins', $active_plugins );    
    }
    add_action( 'init', 'activate_plugin_via_php' );<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /homepages/29/d782843215/htdocs/Loveandover/Migrate/wp-content/themes/herald/functions.php:141) in <b>/homepages/29/d782843215/htdocs/Loveandover/Migrate/wp-includes/pluggable.php</b> on line <b>1531</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /homepages/29/d782843215/htdocs/Loveandover/Migrate/wp-content/themes/herald/functions.php:141) in <b>/homepages/29/d782843215/htdocs/Loveandover/Migrate/wp-includes/pluggable.php</b> on line <b>1534</b><br />