There's an encrypted mode but it's missing many features and in my experience most people use it rarely or never. The default mode is not e2e encrypted.
It uses standard transport encryption for all communication. End to End encryption is available for direct messages. It isn't used for groups, where real E2E is very difficult and complex and AFAIK nobody does it well, and channels, where it doesn't seem to have much point.
andai|5 years ago
emteycz|5 years ago
ufmace|5 years ago