This update is no longer available. To fix the issues that are described in this article, install the latest Microsoft Exchange Server update from the following Microsoft Learn article:
Exchange Server build numbers and release dates
Microsoft provides download files only for N-2 versions for an Exchange Server cumulative update (CU), where "N" is the latest CU. The latest CU can be used to recover servers that are running Exchange Server. This includes servers that have a previous CU installed.
Cumulative Update 19 for Microsoft Exchange Server 2013 was released on December 19, 2017. Several nonsecurity issues are fixed in this cumulative update or a later cumulative update for Exchange Server 2013.
Issues that this cumulative update fixes
This cumulative update adds support for .NET Framework 4.7.1. This cumulative update also fixes the issues that are described in the following Microsoft Knowledge Base articles:
4046316 MAPI over HTTP can't remove client sessions timely if using OAuth and the resource has a master account in Exchange Server 2013
4046205 W3wp high CPU usage in Exchange Server 2013
4046182 Event ID 4999 or 1007 if diagnostics service crashes repeatedly in Exchange Server 2013
4056329 Can't access EWS from Outlook/OWA add-ins via makeEwsRequestAsync in Exchange Server 2016 and Exchange Server 2013
4045655 Description of the security update for Microsoft Exchange: December 12, 2017