What is supported for Calendar integration is outlined in the documentation, anything that doesn't show there, can be considered as not supported
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/jabber/11_8/cjab_b_feature-configuration-cisco-jabber118/cjab_b_feature-configuration-cisco-jabber118_chapter_0110.html
HTH
java
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