As mentioned in an earlier blog post the general Microsoft mainstream support for SharePoint Server 2013 will end by April 10, 2018.
Please note that all SharePoint servers and farms running a patch level lower than April 2017 CU will be unsupported after this date! To prevent falling out of support you should plan to upgrade your farm to the latest patch level.

Roger Haueter
I'm a passionate leader and Senior Systems Architect based in Bern, Switzerland. I primarily focus on cloud strategy consulting for Microsoft 365.