Peter Lieven from KAMP.de discovered a problem with TurnKey 13.0 where the OpenSSH ECDSA key is not regenerated on firstboot like the RSA and DSA host keys.

We've issued a signed hotpatch to TurnKey Core 13.0 that regenerates the ECDSA SSH host key. TurnKey deployments that have not disabled automatic security updates (it's on by default) will have their ECDSA SSH host key regenerated automatically within the next 24 hours.