Hi, 1. If I upgrade the database from calendarserver 5.x to 7.x using calendarserver_upgrade script, then I see the following error in error.log, when trying to connect via caldav client (note that this does not happen for fresh installation). Any help in debugging this would be appreciated. =============================================================== 2016-01-27 02:54:58+0530 [BinaryBoxProtocol,1,] Unhandled Error Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/twisted/protocols/amp.py", line 954, in _commandReceived deferred = self.dispatchCommand(box) File "/usr/lib/python2.7/dist-packages/twisted/protocols/amp.py", line 1011, in dispatchCommand return maybeDeferred(responder, box) File "/usr/lib/python2.7/dist-packages/twisted/internet/defer.py", line 150, in maybeDeferred result = f(*args, **kw) File "/usr/lib/python2.7/dist-packages/twisted/protocols/amp.py", line 1100, in doit return maybeDeferred(aCallable, **kw).addCallback( --- <exception caught here> --- File "/usr/lib/python2.7/dist-packages/twisted/internet/defer.py", line 150, in maybeDeferred result = f(*args, **kw) File "/usr/lib/python2.7/dist-packages/calendarserver/accesslog.py", line 685, in logStats self.observer.logStats(stats) File "/usr/lib/python2.7/dist-packages/calendarserver/accesslog.py", line 378, in logStats self.systemStats = SystemMonitor() File "/usr/lib/python2.7/dist-packages/calendarserver/accesslog.py", line 587, in __init__ "cpu count" : psutil.NUM_CPUS if psutil is not None else -1, exceptions.AttributeError: 'module' object has no attribute 'NUM_CPUS' 2016-01-27 02:54:58+0530 [BinaryBoxProtocol,1,] Amp server or network failure unhandled by client application. Dropping connection! To avoid, add errbacks to ALL remote commands! Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/twisted/protocols/amp.py", line 978, in ampBoxReceived self._commandReceived(box) File "/usr/lib/python2.7/dist-packages/twisted/protocols/amp.py", line 957, in _commandReceived deferred.addCallback(self._safeEmit) File "/usr/lib/python2.7/dist-packages/twisted/internet/defer.py", line 317, in addCallback callbackKeywords=kw) File "/usr/lib/python2.7/dist-packages/twisted/internet/defer.py", line 306, in addCallbacks self._runCallbacks() --- <exception caught here> --- File "/usr/lib/python2.7/dist-packages/twisted/internet/defer.py", line 588, in _runCallbacks current.result = callback(current.result, *args, **kw) File "/usr/lib/python2.7/dist-packages/twisted/protocols/amp.py", line 989, in _safeEmit aBox._sendTo(self.boxSender) File "/usr/lib/python2.7/dist-packages/twisted/protocols/amp.py", line 667, in _sendTo proto.transport.loseConnection() exceptions.AttributeError: 'DispatchingSender' object has no attribute 'transport' 2016-01-27 02:54:58+0530 [-] [caldav-1] [BinaryBoxProtocol,client] [calendarserver.accesslog#error] Unable to format event {'log_level': <LogLevel=error>, 'log_logger': <Logger 'calendarserver.accesslog'>, 'log_source': None, 'log_legacy': <twext.python.log.LegacyFormatStub object at 0xb4fccdcc>, 'format': '[calendarserver.accesslog#error] %(log_legacy)s', 'log_time': 1453843498.495608, 'log_namespace': 'calendarserver.accesslog', 'logLevel': 40, 'log_format': <twisted.python.failure.Failure twisted.protocols.amp.UnknownRemoteError: Code<UNKNOWN>: Unknown Error>}: Log format must be unicode or bytes, not <twisted.python.failure.Failure twisted.protocols.amp.UnknownRemoteError: Code<UNKNOWN>: Unknown Error> 2016-01-27 02:55:55+0530 [-] [calendarserver.tap.util#error] Unable to determine memory usage of PID: 2447 ('Process' object has no attribute 'get_memory_info') ======================================================================== 2. Also, after upgrade, I am unable to create any tasks. As a matter of fact, the calendar itself is not shown in the available calendars for adding tasks in Thunderbird. Any idea on what could be causing this? Again the same config for a fresh installation does not pose this problem. 3. Finally, I am attaching a patch that I have used for calendarserver. If I don't do that, my error.log is filled with errors like "2016-01-20 17:31:24+0100 [-] [directoryproxy] /usr/bin/twistd: Unknown command: caldav_directoryproxy". Thanks, Rahul.