MT4 and MT5 both remain widely used, and both fully support automated trading through Expert Advisors — which raises a genuinely practical question for anyone getting started: does it actually matter which one you use?
The core technical differences
Programming language. MT4 uses MQL4; MT5 uses MQL5 — a more modern, capable language with more built-in functionality. This matters more to EA developers than to end users, but it does mean a given EA is generally built for one platform specifically, not automatically compatible with both.
Order execution model. MT5 supports a more flexible order and position system, including proper hedging and netting mode options depending on your broker's configuration; MT4's model is simpler and, for many strategies, functionally sufficient.
Backtesting capability. MT5's strategy tester is generally considered more capable — supporting multi-currency testing and more realistic execution modeling — which matters more to someone developing or rigorously testing a strategy than to someone simply running a finished EA.
Symbol and instrument support. MT5 was built with broader instrument support in mind from the outset (stocks, futures, and other asset classes alongside forex), while MT4 remains more narrowly focused on forex and CFDs — relevant mainly if you're interested in trading beyond currency pairs and metals.
What actually matters for most EA users
For someone simply running a finished EA rather than developing one, the practical decision usually comes down to a much simpler question: which platform is your specific EA built for, and does your broker support it well?
Most newer EA development happens on MT5 at this point, since it's the more actively developed platform and the language it's built on offers more capability to developers. That said, MT4 remains extremely widely supported by brokers and still runs the vast majority of existing EAs without issue — it hasn't become obsolete, just older.
Broker support is worth checking directly
Not every broker supports both platforms equally well — some have stronger, more mature MT5 offerings, others still favor MT4, and a few have begun phasing one out in favor of the other. This is worth confirming directly with your specific broker rather than assuming universal support, particularly if you already have a broker relationship and are evaluating an EA built specifically for one platform.
The practical recommendation
If you're choosing a platform with a completely blank slate — no existing broker relationship, no EA already selected — MT5 is generally the more future-proof choice, given it's the more actively developed platform with broader capability. If you already have a specific EA in mind, the decision is largely made for you: use whichever platform that EA is actually built for, since MT4 and MT5 EAs are not interchangeable despite the similar branding.
QMS Trading's Gold and Forex Editions are both built specifically for MT5, taking advantage of its more capable execution and testing environment. The full setup guide covers exactly what's needed to get either edition running.