If your users already have a common POP, IMAP, or SOAP e-mail client that comes with Linux or Windows, they can continue to use it to access their GroupWise mailboxes. Users of non-GroupWise e-mail clients retain the feature sets of their familiar e-mail clients, but many GroupWise features are not available to such users because they are not offered in POP, IMAP, and SOAP e-mail clients. For example, calendaring is available only if the POP, IMAP, or SOAP client supports iCal.