Office Communicator and Office Communications Server products will reach the end of extended support during within the next two years (1/9/2018). Also Lync 2010 transitioning from mainstream to extended support as of April 12, 2016.
This is the right time for your to migrate your existing OCS R2 / Lync 2010 environment to either Skype for Business Server 2015 or Skype for Business Online.
Read the below TechNet article to begin your Migration to Skype for Business Server 2015
If you choose Office 365,
For migrating to Skype for Business Online, OCS R2 customers requires de-commissioning the existing system, enabling the users in Office 365, and having each user re-create their contact lists and re-curring meetings.
For Lync 2010 customers, planning for Hybrid deployment and migrating users to Skype for Business Online is a possible option.
To take advantage of the latest innovations with Office 365, migrating to Skype for Business Online is the best option and you can take advantage of Microsoft Fasttrack to begin your journey to the cloud.
Count down started... Get ready to begin your migration soon...