Hello,

on newly installed Kolab 16 on CentOS 7.5 I wanted to change invitation policy handling to automatic processing of replies.
After reading the docs and changing ACT_MANUAL to ALL_UPDATE_AND_NOTIFY in /etc/kolab/kolab.conf I noticed that iTip replies are not received and event status or participant/assignee status is not changing. Same thing is happening for events and tasks.
How to reproduce:

• Add ALL_UPDATE_AND_NOTIFY to kolab.conf
• restart wallace service
• organize meeting/event in your calendar and add participant
• when participant clicks accept no iTip reply is sent to organizer and no status is changed in organizer's calendar

After looking at log I noticed this error:
[root@mail ~]# tail -f /var/log/kolab/pykolab.log

2018-11-13 10:53:37,057 pykolab.wallace ERROR [11644] Module 'invitationpolicy' - Unknown error occurred; NameError("global name 'random' is not defined",)
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/wallace/modules.py", line 117, in execute
    return modules[name]['function'](*args, **kw)
  File "/usr/lib/python2.7/site-packages/wallace/module_invitationpolicy.py", line 372, in execute
    done = processor_func(itip_event, policy, recipient_email, sender_email, receiving_user)
  File "/usr/lib/python2.7/site-packages/wallace/module_invitationpolicy.py", line 600, in process_itip_reply
    sender_attendee, itip_event['xml'].get_comment())
  File "/usr/lib/python2.7/site-packages/wallace/module_invitationpolicy.py", line 1294, in send_update_notification
    seed = random.randint(0, 6)
NameError: global name 'random' is not defined

Indeed after looking at module_invitationpolicy.py random isn't defined and after adding import random and restarting wallace it works, iTip is received and status is updated in calendar.

[root@mail ~]# rpm -qv pykolab
pykolab-0.8.10-1.4.el7.kolab_16.noarch

Let me know if you need any additional info.