If you happen to use the Debian package gajim-omemo, please update to 1.0.0-2 on unstable/testing, or to 1.0.0-2~bpo8+1 on stable (a.k.a. Jessie a.k.a. 8). On unstable/testing, you may also try 1.2.0-1 from experimental. You will need the new version to be able to communicate securely with users of the latest Conversations release. In case of problems, just write to me or file a bug. Thanks!