Run this in Dirsync Powershell:
Also upgrade AD Schema to 2013. (It has something to do with the AD attributes used for Lync 2013)
Update the schema of your local Active Directory to Exchange 2013. After you do this, Exchange 2013-specific attributes are available, and directory synchronization can write the values to your local Active Directory domain.
Note If Exchange 2010 was previously installed in your on-premises environment, and you extend the schema to Exchange 2013, you will be able to install additional Exchange 2010 servers at a later time, if it is necessary. If you have never had Exchange 2010 running in your on-premises environment, and you extend the schema to Exchange 2013, you won’t be able to install additional Exchange 2010 servers in your on-premises environment.