The company said grommunio, which runs on Linux, would provide independent management of email, contacts, calendar, chat, video conferencing and file sharing in real time.

The announcement comes at a time when Microsoft Exchange Server has been under attack from numerous actors, due to vulnerabilities known as ProxyShell and ProxyLogon.

Different packages are offered to both individuals and companies as subscriptions, along with support.

grommunio was formerly known as gramm and is released under a licence known as AGPLv3. It is developed in line with open standards and supports both the older RPC over HTTP protocol and the Outlook standard protocol MAPI over HTTP.

The package also includes Exchange ActiveSync for mobile devices and various standard protocols like CalDAV (calendar), CardDAV (address book), IMAP, POP3, SMTP, and LDAP, as well as Active Directory (for syncing of user accounts).

grommunio also supports database sharing and the storage backend is flexible to allow expansion of a setup.

A community edition is free for use by up to five users.