[horde] hoster changes from centOS 6 to centOS7

[Frank Lienhard]

OK, I have to move my webserver, because my hoster is changing from
centOS6 to 7.

I use shared hosting (uberspace.de) and they provide some migration service.

which means among other thing, that you have both instances available
for some time.
I've done the change and all the files where transfered.

But the there is no version of pear installed on the new server.
And the new server is running PHP 7  (7.2.  7.3./ 7.4.).

I'm a bit lost how to get horde working again...