While in Standard Edition you have to make sure State is not Busy and IsReadyForUpgrade is True under UpgradeDomains for the same upgrade domain. In Enterprise Edition if State is Ready and IsReadyForUpgrade is True under UpgradeDomains for the same upgrade domain then you are good to go otherwise try to resolve the issue if State is Busy or InsufficientActiveFrontEnds. In the result you can get three different values. Run Get-CsPoolUpgradeReadinessState on Standard Edition Server or Front End Server in Enterprise Edition to verify the readiness state. Verify the upgrade readiness state of your SfB pool.If Lync Server 2013 still exist in your topology you can download the CU here. Download the latest cumulative updates.Below are the steps in detail which you need to perform at the time of upgrade. Though steps are common for all kind of topologies but sequence may change based on the configuration. When I say simple topology it means your SfB infra has single site or two site with site resiliency configuration while complex topology means you have multiple sites with different versions and editions of SfB. Your existing SfB infra may have simple topology or complex topology.

Part I of this blogpost will describe the planning phase while Part II with cover the execution and verification. To make this process simple, Lets divide this process in three phases. In this blogpost, I’ll cover the step by step process to update Skype for Business server infrastructure. It is applicable in all circumstances either personal devices or business infrastructure. To update existing system or technology is a continual process in Information Technology.

Lync 2013 upgrade to skype for business