Microsoft has released Cumulative Update 11 for Exchange Server 2013.
From the Microsoft Exchange Team blog:
The release includes fixes for customer reported issues, minor product enhancements and previously released security bulletins. A complete list of customer reported issues resolved can be found in Knowledge Base Article KB3099522. Customers running any previous release of Exchange Server 2013 can move directly to Cumulative Update 11. Customers deploying Exchange Server 2013 for the first time may skip previous releases and start their deployment with Cumulative Update 11 directly.
Cumulative Update 11 does not include updates to Active Directory Schema, but may add additional RBAC definitions to your existing configuration. PrepareAD should be executed prior to upgrading any servers to CU11. PrepareAD will run automatically during the first server upgrade if Setup detects this is required and the logged on user has sufficient permission.
Cumulative Update 11 also includes a change in behavior when deploying/administering Exchange Server 2013 in a co-existent manner with Exchange Server 2010 or 2016. These changes are outlined in the following blog article: Exchange Management Shell and Mailbox Anchoring.
The changed behavior for PowerShell management is important if you have a co-existence deployment, and in particular a geographically distributed deployment. You may need to do some internal education with your IT team, and review any scripts or other tools that rely on PowerShell access to Exchange.
Also note that CU11 fixes the bug that allowed an Exchange 2016 mailbox server to be added to an Exchange 2013 DAG.
Cumulative Update 11 is available for download here.
For deployment steps refer to this guide to installing cumulative updates for Exchange Server 2013.