[horde] Transfer of Horde

[Ralph Ballier]

Hello,
I have horde from an old Linux server under Slackware to a server  
under Ubuntu 16.04.3 LTS transfer. Also the database should run on the  
new server.

So far I have proceeded as follows:
- On the new server: apt install horde (I think that was ok)
- On the old server I have with phpMyAdmin the whole database exported  
except the table horde_vfs (since there was a problem with the later  
import)
- On the new server I have imported the exported database again
- I have the entire old directory /www/htdocs/horde transferred and  
some data in config/conf.php adjusted
- When I called afterwards with the webbrowser Horde, the error  
message "PHP Fatal error: Can not use 'string' as classname as it is  
reserved in /usr/share/php/Horde/Css/Parser/vendor/sabberworm/php  
-css-parser/lib/Sabberworm/CSS/Value /String.php on line 5 "
What should I do? Or should I proceed quite differently?