How to check if my OpenSSL supports ALPN?

TheTanadu asked:

I search if my server is running OpenSSL with ALPN support. I need that to know if I have to install OpenSSL again but with ALPN support or I can skip that. I want to build HTTP/2 at DirectAdmin server.
I’ve used openssl version -a | grep -i alpn but nothing showed up.

My system:

CentOS Linux release 7.3.1611 (Core)


OpenSSL 1.0.1e-fips 11 Feb 2013
built on: Mon Feb 20 14:38:48 UTC 2017

My answer:

You need OpenSSL 1.0.2 for ALPN support. You would already have this if you had updated your system. You should do that now.

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