Contributed by pitrh on 2017-05-01 from the it was a step up from telnet once dept.

In a series of commits starting here and ending with this one , Damien Miller completed the removal of all support for the now-historic SSHv1 protocol from OpenSSH

The final commit message, for the commit that removes the SSHv1 related regression tests, reads:

Eliminate explicit specification of protocol in tests and loops over protocol. We only support SSHv2 now.

Dropping support for SSHv1 and associated ciphers that were either suspected to or known to be broken has been planned for several releases, and has been eagerly anticipated by many in the OpenBSD camp.

In practical terms this means that starting with OpenBSD-current and snapshots as they will be very soon (and further down the road OpenBSD 6.2 with OpenSSH 7.6), the arcane options you used with ssh to connect to some end-of-life gear in a derelict data centre you don't want to visit anymore will no longer work and you will be forced do the reasonable thing. Upgrade.

Longtime OpenBSD developer Bob Beck's public reaction on Twitter was to the point:

Goodbye SSH version 1 - Anyone still using you has been delusional for a very long time. https://t.co/43EgGta16k — Bob Beck (@bob_beck) April 30, 2017

Others have described the long-planned move variously as "a mercy killing" and "a cause for major celebrations".

Now is a great time to prepare to decommission or upgrade any equipment that still relies on the long deprecated protocol. You will be making your users safer in the process.