connection failing when connecting to newer ssh server

[jrishel]

Discussed in #396

^{Originally posted by jrishel August 23, 2024}
I'm using ParallelSSH on a RHEL7 host (python 3.6, sourcing ParallelSSH 2.12.0 from pypi. It works connecting to my RHEL7 and RHEL8 hosts, but on RHEL9, the connection fails. at the OS level, I can use SSH keys to connect without issue. the error the RHEL9 ssh server indicates is:
sshd[986124]: userauth_pubkey: key type ssh-rsa not in PubkeyAcceptedAlgorithms [preauth]

Is there a way to tell pssh.clients to start using newer algo keys? I'd rather update that than go to my RHEL9 hosts and tell them to start accepting legacy algo keys? I did test that setting RHEL9 to legacy crypto policy lets the SSHClient connect, but that's not ideal.