Today I figured out why Outlook 2010 and 2013 doesn’t display this information anymore.
Missed conversations and pstn-calls that the user calls out still work fine.
To get it working again uninstall these updates:
KB3101496
KB3114502
KB3114502
KB3114351
And it’s working again. This isn’t a permanent solution because these are security updates for Lync client.
Hopefully Microsoft will fix this bug in future updates.
** Update 10/2 ***
Yesterday Microsoft released the update.
https://support.microsoft.com/en-us/kb/3114732
It will fix missed calls functionality without UM-role needed!