Tiki and ((Cypht)) webmail interoperability started with ((Tiki20)). Major work has been done since that time in Cypht, and in Tiki 21, 22, 23 and 24. Work is ongoing, so it's recommended to run the latest 24.x from Git or ((dev:Daily Build)). Most enhancements and many fixes will not be backported to ((Tiki21)) LTS as there are lots of changes.