[sync] iPhone going crazy with latest ActiveSync update (2.8.1)

[lst_hoe02 at kwsoft.de]

Hello,

yesterday i was doing a pear-upgrade which updated Horde_ActiveSync  
from 2.7.3 to 2.8.1. With this update the test iPhone with iOS 7.0.2  
is not able to sync e-mail any more. It syncs over and over again  
draining the battery like hell.

The message in the ActiveSync log is

2013-10-01T11:18:00+02:00 ERR: [26871] Attempting a SYNC_COMMANDS, but  
device failed to send synckey. Ignoring.

which is repeated over and over again. I have switched of the Phone,  
reset the ActiveSync state, restart the webserver, cleaned the cache  
and restartet again but the problem persists. Any idea what went wrong?

Regards

Andreas