MetaTrader 5 has been under development for two years and beta testing will finally begin this summer. MT5 is a complete rewrite of the MetaQuotes platform and is not backward compatible with MT4. So if you purchased expert advisors to trade on MT4 and you plan to use MT5, you might as well throw those MT4 EAs away. They won�t work on MT5.
MetaTrader 5 offers several new features that may make it necessary for retail traders to adjust to new terminology and, possibly, a new way of thinking about order processing and trade management.
First, a new order type - Exchange - will now enable trading of stocks, futures and options directly from the MT5 platform in addition to the Forex order to which MT4 traders are already accustomed.