Collaboration suite and email developers , positioned as an alternative to MS Exchange, open source policy. Starting from release the project will stop publishing binary builds of Zimbra Open Source Edition and will only release the commercial version of Zimbra Network Edition. Moreover, the developers do not plan to release Zimbra 9 sources to the community and will develop Zimbra 9 in the form of a proprietary product. The old Zimbra 8.8.15 branch will remain open and maintained until December 31, 2024.
Source: opennet.ru