[horde] Cannot update the Horde Configuration

[Ferdinand Gruber]

Hi,

I upgraded horde to the latest version 5.2.17  using the command

    pear upgrade -a -B horde/groupware

After the upgrade I am not able to enter the configuration page of horde 
using the web interface.

I get the error:

    Uncaught TypeError: Argument 1 passed to
    IMP_Application::exceptionHandler() must be an instance of
    Exception, instance of ParseError given in
    /srv/www/htdocs/horde/imp/lib/Application.php:610
    Stack trace:
    #0 [internal function]:
    IMP_Application->exceptionHandler(Object(ParseError))
    #1 {main}
       thrown [pid 23680 on line 610 of
    "/srv/www/htdocs/horde/imp/lib/Application.php"]

My horde server is running under suse leap 42.2. HTTP server is apache2 
working with php7.

Thank you in advance for help.

-- 
Regards from Austria
Ferdinand Gruber