As of October 31, 2018, Microsoft Office 365 will no longer support TLS 1.0 and 1.1

[Falco]

And TLS 1.3 since

Discourse new Base Image

We just released a new base image with support for TLS 1.3 . [image] Users will need to rebuild from the command line to get this new feature. We also packed a few dependencies update, moved from Ubuntu 16.04 to Debian Buster and updated our SSL cyphers list to match https://ssl-config.mozilla.org/ intermediate config and updated to Ruby 2.6.4. Due to all that we will make the command line rebuild mandatory later this week.