Zimbra Collaboration Suite Alternatives for Linux

Kolab Community is a comprehensive, free, and open-source groupware suite designed for collaborative work. It provides integrated email, calendar, contacts, and tasks functionalities, empowering individuals and teams to communicate and manage their data efficiently and with a strong focus on data privacy.

Kopano is a versatile open-source groupware suite offering email, calendaring, contacts, and online collaboration tools for businesses and organizations. It provides flexible deployment options, including on-premises and hosted solutions, with strong focus on data privacy and security.

Zarafa is an open-source groupware and email server platform, providing powerful collaborative features similar to Microsoft Exchange but with flexibility and cost advantages. It offers email, calendaring, contacts, and task management.

iRedMail is a comprehensive, free, and open-source mail server solution designed for ease of deployment and maintenance. It bundles popular components like Postfix, Dovecot, and Roundcube, providing robust email, calendar, and contact management capabilities.

mailcow is a comprehensive open-source mail server suite built on Docker, providing a robust and secure platform for self-hosting email. It integrates various components like Postfix, Dovecot, and SOGo into a single, easy-to-manage system.

OX Open-Xchange is a comprehensive web-based suite designed for communication, collaboration, and office productivity, offering features like email, calendaring, task management, and document sharing, seamlessly integrating across devices.