Why does SSH have v1 and v2?  Honest question, I don&#x27;t know the protocol.  I would guess it&#x27;s because v1 was too brittle to be upgraded.<p>SSH and TLS have very few implementations... and there also seem to be incompatible versions there, at least with SSL 2.0 and 3.0.  That approach might work for the ecological niche of those protocols, but I don&#x27;t think it would have worked for HTTP.<p>There are orders of magnitude more HTTP implementations than DNS, DHCP, TLS, SSH, etc.  That&#x27;s one reason for its wide adoption.