HTTP/2 replaces SPDY/3
Microsoft Edge removes support for the experimental SPDY/3 protocol and implements the HTTP/2 standard.
TCP Connection Sharing (also known as SPDY/3) was an experimental precursor to HTTP/2 that implemented some network use optimizations. It is being removed.
HTTP/2 will be used by Microsoft Edge on SSL/TLS connections (https) when supported by the host server. Microsoft Edge will fall back to HTTP/1.1 when HTTP/2 is not available or the connection is not secure.
Client-side developers will see HTTP/2 noted in the F12 developer tools Network tool where applicable.