The Nokia asha smartphones and select models of Nseries smartphones and newer s60 and Symbian^3 handsets running symbian os 9.x or Symbian^3 support the Mail for Exchange software, which is compatible with Microsoft Exchange Server Active Sync and Direct Push, allowing the Nokia smartphones to receive push email as well as sync contact lists, calendars, and tasks with Exchange servers.Global Address Lookup is also supported, starting with version 2 of the Mail for Exchange software.
Extending the "push" to the last delivery step is what distinguishes push email from polling email systems.
The reason that polling is often used for the last stage of mail delivery is that, although the server mail delivery agent would normally be permanently connected to the network, it does not necessarily know how to locate the client mail user agent, which may only be connected occasionally and also change network address quite often.
This makes retrieval of new messages more flexible than a purely push system, because the client can choose whether to download new message data.
Although push email had existed in wired-based systems for many years, one of the first uses of the system with a portable, "always on" wireless device outside Asia was the Black Berry service from Research In Motion.
In Japan, "push email" has been standard in cell phones since 2000.
Apple's i Phone, i Pad and i Pod Touch support Hotmail push email.For example, a user with a laptop on a Wi-Fi connection may be assigned different addresses from the network DHCP server periodically and have no persistent network name.When new mail arrives to the mail server, it does not know what address the client is currently assigned.Yahoo Mail may be pushed to an Android device, as Android now supports IMAP4 (as of September 2015).An alternative for Yahoo Mail is to install the free Yahoo Mail app, which provides instant push email.The Internet Message Access Protocol (IMAP) provides support for polling and notifications.