[horde] Call to undefined function Horde\Http\Server\getallheaders()

[A.Schulze]

Hello,

installed horde6 + wicked + nginx and got this failure on https://horde.example/wicked

A fatal error has occurred
Call to undefined function Horde\Http\Server\getallheaders()
in /horde6/vendor/horde/http_server/src/RequestBuilder.php:69

1. require_once() /horde6/web/wicked/index.php:3
2. require() /horde6/vendor/horde/wicked/index.php:12
3. Horde\Http\Server\RequestBuilder->withGlobalVariables() /horde6/vendor/horde/wicked/display.php:31

any further information needed?

Andreas