Today, node servers cut the connection when they receive upgrade headers, which isn't advised in the http/1.1 or http/2 specs. As http/2 gains a wider mindshare, h2c will see an uptick in adoption in intra-datacenter use, so if node wants to continue being viable in microservice architectures, it makes sense to at least play nicely with h2c clients, even if it doesn't want to implement h2c by default.

Instead, node servers should ignore the upgrade header and treat it as a normal request if the implementor hasn't defined anything special to do to it.