14 months ago: "No. But TLS!" https://news.ycombinator.com/item?id=11556762
7 months ago: "421" https://news.ycombinator.com/item?id=13022596
Maybe it would be worth the time to test out the various implementations if someone has not already done so?
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Doing some preliminary research, support is still a working draft https://datatracker.ietf.org/doc/draft-bishop-httpbis-http2-... source: https://daniel.haxx.se/blog/2016/08/18/http2-connection-coal...