While HTTP/2 does exist, as others have already said, this is about version 2.0 of an _implementation_ of a protocol, not versions of the protocol itself.
OpenSSL hasn't had a 2.0 release (1.1.0 is in beta), but has had many releases over the last seven years, and is very widely used. Netscape Security Services is now at 3.21, but that doesn't mean it's three times as widely used as OpenSSL. Mostly this just shows that different open source projects use different release numbering schemes, and can't be directly compared.
(The same is true of protocol versioning. That SSL had versions 2.0 and 3.0 and TLS is working on 1.3, doesn't mean TLS isn't used as much as SSL was, it means that TLS designers had learnt from SSL mistakes, and haven't had to introduce a totally incompatible version.)