This means that if you've got 38 subscribers in UC that need to be configured for Office 365, you need to create 2 UM service accounts and assign 19 of your users to the first account, and the remaining 19 to the second UM account. If you've got several hundred users, you can see where this could be a bit of an administrative task until Microsoft changes their deployment restrictions.
It may make more sense if you have a look at the configuration guide to understand the task list:
IntroductionCUCM Routing RulesDial String implementation PolicyCUCM Routing LogicSIP URI Call Routing Analysis+++ Case Study: 1 ++++++ Case Study: 2 +++Conclusion
Over the last few months, I have had the privilege of working on SI...
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...