Ouch, didn't see your question. Self-upgrade can be initiated by chatting with the agent, it can be manually called via Actions->Upgrade web ui or if you experienced errors during chatting with the agent (tool errors) you can trigger self-repair from the Runs tabs in agent's page. I am aiming for an auto-repair in future but right now the main trigger is basically chating with the agent: chat, and if you want any new features or there are errors you just request upgrade in chat - the LLM will send the context to the builder agent.
Connections and MCP connections (these are different) credentials are saved on the Airlock's (platform's) side. So the credentials are kept after an agent upgrade. Permissions are defined in the agent's code (admin/user/public) and are auto-updated.
Rollbacks are not possible right now. But every agent's update is a git commit. And every agent has to write migrations. In the near future an option to rollback to a specific build will be added. Right now I think you can try to just request an upgrade to rollback, I think the builder agent will be able to look into git history and rollback. But this is not really tested.
As I mentioned before this is an alpha version.