GitHub has recently changed its policies vs SSH keys (see Generating a new SSH key and adding it to the ssh-agent - GitHub Docs).
The previous SSH lib (JSch) used by the Eclipse JGit lib (used by Simplicité to manage the modules’ Git repo) was not compliant with these new policies.
We have therefore switched from JSch to Apache Mina as recommended by the JGit team.
This is transparent at Simplicité platform level but it is now required that remote hosts accessed over SSH (e.g github.com, gitlab.com, etc.) are registered as well known hosts by the underlying SSH environment.
For instance, on Linux you need to make a first connection attempt and accept the host as a well known host (e.g. ssh git@github.com) or add it explicitly (e.g. ssh-keyscan -t rsa github.com)
This change applies to all 5.x branches as of revision 5.1.37.
If you experience some error messages when puhing/pulling to/from a module’s remote repository over SSH from Simplicité, chances are this is related to an unknown host (note that in previous JSch-based implemementation no host checking was done by default).
NB: as a reminder, if you are using our Docker images an environment variable allows you add a list of hostnames as known hosts at container’s startup. E.g: -e SSH_KNOWN_HOSTS="github.com gitlab.com" (see Simplicité® documentation/90-operation/docker, and a docker compose example here)