If this is the server side integration, O365 doesn't show as supported
https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/im_presence/exchange_integration/10_5_1/CUP0_BK_IBB369E9_00_imp-exchange-integration-guide-105/CUP0_BK_IBB369E9_00_imp-exchange-integration-guide-105_chapter_010.html
If this is the client side integration, these are the requirements
https://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
if this helps, please rate