[horde] HTTP 500 Error on CalDAV sync

[Michael Borgelt]

Hello.
I got the following error on CalDAV sync with latest Horde 6.0.0:

HORDE 2026-07-01T10:08:32+02:00 error: [kronolith] Error: Typed  
property Horde\Memcache\MemcacheApi::$logger must not be accessed  
before initialization in  
/srv/horde/vendor/horde/memcache/src/MemcacheApi.php:207
Stack trace:
#0 /srv/horde/vendor/horde/memcache/src/MemcacheApi.php(1000):  
Horde\Memcache\MemcacheApi->init()
#1 [internal function]: Horde\Memcache\MemcacheApi->__unserialize()
#2 /srv/horde/vendor/horde/timezone/lib/Horde/Timezone.php(274): unserialize()
#3 /srv/horde/vendor/horde/timezone/lib/Horde/Timezone.php(143):  
Horde_Timezone->_extractAndParse()
#4 /srv/horde/vendor/horde/kronolith/lib/Event.php(760):  
Horde_Timezone->getZone()
#5 /srv/horde/vendor/horde/kronolith/lib/Application.php(1067):  
Kronolith_Event->toiCalendar()
#6 /srv/horde/vendor/horde/core/lib/Horde/Registry.php(1295):  
Kronolith_Application->davGetObject()
#7  
/srv/horde/vendor/horde/dav/lib/Horde/Dav/Calendar/Backend.php(154):  
Horde_Registry->callAppMethod()
#8  
/srv/horde/vendor/sabre/dav/lib/CalDAV/Backend/AbstractBackend.php(133):  
Horde_Dav_Calendar_Backend->getCalendarObject()
#9  
/srv/horde/vendor/sabre/dav/lib/CalDAV/Backend/AbstractBackend.php(113):  
Sabre\CalDAV\Backend\AbstractBackend->validateFilterForObject()
#10 /srv/horde/vendor/sabre/dav/lib/CalDAV/Calendar.php(354):  
Sabre\CalDAV\Backend\AbstractBackend->calendarQuery()
#11 /srv/horde/vendor/sabre/dav/lib/CalDAV/Plugin.php(598):  
Sabre\CalDAV\Calendar->calendarQuery()
#12 /srv/horde/vendor/sabre/dav/lib/CalDAV/Plugin.php(258):  
Sabre\CalDAV\Plugin->calendarQueryReport()
#13 /srv/horde/vendor/sabre/event/lib/WildcardEmitterTrait.php(89):  
Sabre\CalDAV\Plugin->report()
#14 /srv/horde/vendor/sabre/dav/lib/DAV/CorePlugin.php(690):  
Sabre\DAV\Server->emit()
#15 /srv/horde/vendor/sabre/event/lib/WildcardEmitterTrait.php(89):  
Sabre\DAV\CorePlugin->httpReport()
#16 /srv/horde/vendor/sabre/dav/lib/DAV/Server.php(472):  
Sabre\DAV\Server->emit()
#17 /srv/horde/vendor/sabre/dav/lib/DAV/Server.php(253):  
Sabre\DAV\Server->invokeMethod()
#18 /srv/horde/vendor/sabre/dav/lib/DAV/Server.php(321):  
Sabre\DAV\Server->start()
#19 /srv/horde/vendor/horde/rpc/lib/Horde/Rpc/Webdav.php(67):  
Sabre\DAV\Server->exec()
#20 /srv/horde/vendor/horde/horde/rpc.php(199):  
Horde_Rpc_Webdav->getResponse()
#21 /srv/horde/vendor/horde/horde/rpc/index.php(15): require('...')
#22 /srv/horde/web/horde/rpc/index.php(3): require_once('...')
#23 {main} [pid 531169 on line 154 of  
"/srv/horde/vendor/horde/dav/lib/Horde/Dav/Calendar/Backend.php"]

Regards
Michael.

-- 
Michael Borgelt
Email: mborgelt at borgelt.org