HTTP/2
networkingThe second major version of the Hypertext Transfer Protocol, offering significant performance improvements over HTTP/1.1 through multiplexing and header compression.
Pronunciation
Correct
H-T-T-P-two
/eɪtʃtiːtiːpiːtuː/
The HTTP portion is spelled out (H-T-T-P) and the version number is said as 'two'. The IETF RFC uses the written form HTTP/2.
Source: www.rfc-editor.org(official spec)