In V2.3-Beta4
You can no longer see the CSS.
You can change most settings, but not test e-mail sending.

This might be because of the path change of modules in cms 2.3-4

[14-Jul-2019 03:03:44 Europe/Oslo] PHP Warning: 
file_get_contents(/home/username/public_html/cmstest6/modules/Statistics/templates/defaulttopx.tpl):
failed to open stream: No such file or directory in
/home/username/public_html/cmstest6/assets/modules/Statistics/Statistics.module.php
on line 1979
[14-Jul-2019 03:03:44 Europe/Oslo] PHP Warning: 
file_get_contents(/home/username/public_html/cmstest6/modules/Statistics/templates/defaultemail.tpl):
failed to open stream: No such file or directory in
/home/username/public_html/cmstest6/assets/modules/Statistics/Statistics.module.php
on line 1992
[14-Jul-2019 03:03:57 Europe/Oslo] PHP Warning: 
file_get_contents(/home/username/public_html/cmstest6/modules/Statistics/templates/defaulttopx.tpl):
failed to open stream: No such file or directory in
/home/username/public_html/cmstest6/assets/modules/Statistics/Statistics.module.php
on line 1979
[14-Jul-2019 03:03:57 Europe/Oslo] PHP Warning: 
file_get_contents(/home/username/public_html/cmstest6/modules/Statistics/templates/defaultemail.tpl):
failed to open stream: No such file or directory in
/home/username/public_html/cmstest6/assets/modules/Statistics/Statistics.module.php
on line 1992
[14-Jul-2019 03:03:57 Europe/Oslo] PHP Warning: 
file_get_contents(/home/username/public_html/cmstest6/modules/Statistics/templates/defaulttopx.tpl):
failed to open stream: No such file or directory in
/home/username/public_html/cmstest6/assets/modules/Statistics/Statistics.module.php
on line 1979
[14-Jul-2019 03:03:57 Europe/Oslo] PHP Fatal error:  Uncaught
ArgumentCountError: Too few arguments to function CMSModule::SetPreference(), 1
passed in
/home/username/public_html/cmstest6/assets/modules/Statistics/function.templates.php
on line 9 and exactly 2 expected in
/home/username/public_html/cmstest6/lib/classes/class.CMSModule.php:2597
Stack trace:
#0
/home/username/public_html/cmstest6/assets/modules/Statistics/function.templates.php(9):
CMSModule->SetPreference('')
#1
/home/username/public_html/cmstest6/assets/modules/Statistics/action.defaultadmin.php(96):
include('/home/username...')
#2 /home/username/public_html/cmstest6/lib/classes/class.CMSModule.php(1374):
include('/home/username...')
#3 /home/username/public_html/cmstest6/lib/classes/class.CMSModule.php(1459):
CMSModule->DoAction('defaultadmin', 'm1_', Array, NULL)
#4 /home/username/public_html/cmstest6/admin/moduleinterface.php(72):
CMSModule->DoActionBase('defaultadmin', 'm1_', Array, NULL,
Object(CMSMS\internal\Smarty))
#5 {main}
thrown in /home/username/public_html/cmstest6/lib/classes/class.CMSModule.php
on line 2597