Cannot use lexical variable $eventName guzzlehttp

Please help us by providing the following info. Before posting please also check the pinned "Known issues" threads and make sure that you're running the latest available version for your oC release:

Steps to reproduce
1. Log in to OwnCloud
2. Click on Apps

Expected behaviour
Apps page should load

Actual behaviour
HTTP error 500 returned.

Server configuration
Operating system: ArchArm 4.4.45-1-ARCH
Web server : apache 2.4.25-1
Database: mariadb 10.1.21-1
PHP version: php 7.1.1-1
ownCloud version (see ownCloud admin page):
Updated from an older ownCloud or fresh install: Updated
Special configuration (external storage, external authentication, reverse proxy, server-side-encryption):

ownCloud log (data/owncloud.log)

Please paste possible errors in the following code block, see for more info

Cannot use lexical variable $eventName as a parameter name at \/usr\/share\/webapps\/owncloud\/3rdparty\/guzzlehttp\/guzzle\/src\/Event\/Emitter.php#48

Integrity status for oC9+

No errors have been found.

Additional Info
In the Admin pane, the message "Error occurred while checking server setup" is displayed. Loading this page generates the same error message about lexical variable $eventName as listed in the code block above.

I deleted the owncloud directory and reinstalled from the package manager, but saw no change in behaviour.

Web searches show little information, except to suggest an incompatibility between the php version and the guzzlehttp version.

Thank you for any help you can provide.


Appears to be a bug in the guzzle library of version 5.3.0 when used with php 7.1+:

Further information here re: symfony and php 7.1 issues

Ah... Found this:

So OwnCloud not ready for php 7.1.1 yet. Except mine didn't give a warning about a compatibility problem like the link above.
I'll try to roll back to the older php version for now.