Add free SSL certificate to demo.redmine.org
How about adding a free, secure, and very popular Let's Encrypt SSL certificate ? Documentation is at https://letsencrypt.org Optionally, this type of certificate can automatically renew itself to any future new version of TLS.
Any volunteer for adding an SSL certificate to https://demo.redmine.org ? Both me and the Ubertus.org team would be happy, as volunteer, to contribute testing and documentation, if needed.