Exchange Server 2013 Switches to Extended Support
On April 10, Microsoft discontinued mainstream support for Exchange Server 2013 and now offers extended support only. Thus, the messaging system will receive only security updates for the next five years, and no new features.
The transition from Exchange Server 2013 to extended support also ends the provision of quarterly cumulative updates (CU). The last scheduled cumulative update for Exchange Server 2013, number 21, will be released in June 2018. Whether there will be any further cumulative updates has not been explicitly ruled out. So, it is quite possible that the software company, for example in the case of future problems concerning the O365 hybrid deployment, will still release cumulative updates.
Microsoft recommends customers of Exchange Server 2013 to adopt the CU 21 as soon as possible. After September 19, 2018, only systems with cumulative update 21, or any successors, will receive critical security updates. After a three-month grace period, only the most recent cumulative update in the extended support phase is eligible to receive critical security updates.
Microsoft offers five years of mainstream support for its products, followed by another five years of extended support. In extended support, only security updates will be delivered; corrections of errors are only made against payment. After the ten-year support phase, enterprise customers can only make a paid premier support contract with Microsoft for parts of the Office products.