Tiki newsletter is pretty basic but it is tested & stable. It offers tight integration within Tiki. For example it is possible to subscribe a group to a newsletter (and groups can be included in groups). Each newsletter can have distinct permissions to subscribe, send, etc.
Next steps would be to have more of the fancy CRM-like features, like click-through tracking.
Interested community members
Standards and/or other software
Newsletter with text & html patch Has someone tested this?