MT4 vs MT5: compatibility comes before features

Similar names, different programs

MT4 uses MQL4 and commonly compiled .ex4 programs; MT5 uses MQL5 and .ex5 programs. Renaming a file does not convert it. A port requires code changes and behavioral validation, even where language concepts look familiar.

Testing architecture matters

MT5 provides a multi-threaded strategy-testing environment with multi-currency testing support. Platform features alone do not determine model quality: data, costs, order assumptions, and the implementation being tested still matter. Compare a report with the actual terminal and release used to create it.

Account models affect position behavior

In a netting account, activity in a symbol contributes to one net position. A hedging account can retain separate positions in that symbol. An EA expecting independent buy and sell baskets may behave incorrectly or be incompatible on a different model.

Broker offerings determine supported markets and account conditions. Do not infer that every MT5 account offers every asset or uses the same margin rules. Confirm symbol, volume limits, and execution modes with the broker.

A practical compatibility check

Verify the exact executable format, platform build, account model, symbol mapping, and dependencies. Test entries, partial closes, protective orders, and restarts on the intended platform. Treat a converted EA as a new implementation needing its own evidence.

Common questions