About licensing: Cypht changed the license to be the same as Tiki, and thus easier to share code between Tiki and Cypht: https://github.com/cypht-org/cypht/issues/333 LGPL 2.1 (vs GPL) also makes Cypht more pluggable.
The collaboration between Cypht and Tiki has similarities with Roundcube and Kolab (but started a decade later!). In recent years, much of the innovation in Roundcube is driven by Kolab. Similarly, as of 2023, the Tiki project is the main driver of innovation in Cypht.