diff -ur roundcubemail-1.3.0.orig/config/defaults.inc.php roundcubemail-1.3.0/config/defaults.inc.php

--- roundcubemail-1.3.0.orig/config/defaults.inc.php    2017-06-26 20:51:51.000000000 +0200

+++ roundcubemail-1.3.0/config/defaults.inc.php 2017-07-01 11:36:21.094364159 +0200

@@ -514,7 +514,7 @@

 // If your authentication backend supports it, use "UTF-8".

 // Otherwise, use the appropriate character set.

 // Defaults to ISO-8859-1 for backward compatibility.

-$config['password_charset'] = 'ISO-8859-1';

+$config['password_charset'] = 'UTF-8';

 // How many seconds must pass between emails sent by a user

 $config['sendmail_delay'] = 0;

@@ -630,7 +630,7 @@

 //    RewriteRule ^/roundcubemail/[a-zA-Z0-9]{16}/(.*) /roundcubemail/$1 [PT]

 //    Alias /roundcubemail /var/www/roundcubemail/

 // Note: Use assets_path to not prevent the browser from caching assets

-$config['use_secure_urls'] = false;

+$config['use_secure_urls'] = true;

 // Allows to define separate server/path for image/js/css files

 // Warning: If the domain is different cross-domain access to some

@@ -639,11 +639,11 @@

 //    <FilesMatch ".(eot|ttf|woff)">

 //    Header set Access-Control-Allow-Origin "*"

 //    </FilesMatch>

-$config['assets_path'] = '';

+$config['assets_path'] = '/roundcubemail/assets/';

 // While assets_path is for the browser, assets_dir informs

 // PHP code about the location of asset files in filesystem

-$config['assets_dir'] = '';

+$config['assets_dir'] = '/usr/share/roundcubemail/public_html/assets/';

 // ----------------------------------

@@ -737,7 +737,7 @@

 // Since Google shut down their public spell checking service, the default settings

 // connect to http://spell.roundcube.net which is a hosted service provided by Roundcube.

 // You can connect to any other googie-compliant service by setting 'spellcheck_uri' accordingly.

-$config['spellcheck_engine'] = 'googie';

+$config['spellcheck_engine'] = 'pspell';

 // For locally installed Nox Spell Server or After the Deadline services,

 // please specify the URI to call it.

@@ -1138,7 +1138,7 @@

 $config['display_next'] = true;

 // Default messages listing mode. One of 'threads' or 'list'.

-$config['default_list_mode'] = 'list';

+$config['default_list_mode'] = 'threads';

 // 0 - Do not expand threads

 // 1 - Expand all threads automatically

Only in roundcubemail-1.3.0/config: defaults.inc.php.orig

​