Microsoft Teams has proven to be a powerful tool for many organizations, providing for in-depth collaboration between employees and external parties. Many of the features of Microsoft Teams, including chat, meeting, and calling capabilities are mirrored in Microsoft’s Skype for Business tool, which can cause significant end-user confusion. Microsoft has indicated that their future roadmap calls for retiring Skype for Business and replacing it with Teams. Subsequently, it is critical to understand the differences between the coexistence modes provided by Microsoft to ensure that you are limiting disruption to your end users as you migrate users and functionality to Teams. This session discusses the pros and cons of the different coexistence modes, and what clients should expect in each scenario. Limitations of the various options are explored, and real-world best practice implementation advice is provided. Participants will better understand their upgrade options and what to expect along the way. • Understand the differences between the various upgrade and coexistence modes such as Island, Teams Only, Skype for Business Only, Skype for Business with Teams and other variations. • Explore how on-premises Skype for Business factors into the upgrade process, and how hybrid mode becomes a requirement. • Determine to optimal upgrade path for your organization that has the least amount of impact and disruption to your end user population.