Judging from their FAQ, it seems that they encrypt voice end-to-end, but messages only between the client and the server: https://support.wire.com/hc/en-us/arti

Judging from their FAQ, it seems that they encrypt voice end-to-end, but messages only between the client and the server: https://support.wire.com/hc/en-us/articles/203122500-Are-messages-and-calls-encrypted- https://support.wire.com/hc/en-us/articles/203122500-Are-mes... They have features like syncing the read status of messages, so I assume their server knows about all messages and conversations (although maybe not the contents if encrypted properly).