Zimbra officially supports most web browsers.

01.com strongly recommends all customers use Firefox/Mozilla to access Zimbra's webmail, calendars and contacts, and only supports Firefox with the Zimbra administrator interface (aka domain administrator or domain admin) on the Windows, Mac and Linux platforms. Firefox is freely available for all major platforms: http://www.getfirefox.com

Note: Zimbra 5 supports Apple's Safari 3, and iZimbra, part of Zimbra 5, supports the browsers on the Apple iPhone and iPod Touch. There is also a beta J2Me client available for the Blackberry Pearl and like devices.