FYI: Access to the jeelabs.org/.net/.com servers may be disrupted in the next few hours, as I try to switch to a slightly different reverse-proxying setup.
Your friendly sys-admin,
The transition appears to have succeeded. All sites will now redirect to SSL mode, i.e. https: instead of http: - via LetsEncrypt.
Update - I forgot to mention the status page at http://status.jeelabs.org - click on "Forum" or "Website" for details.