Direct answer
MT4 and MT5 are “compatible with” a combination of (1) your device and operating system, (2) a broker’s trading server and account type, (3) the market data and symbol feeds provided by that broker, and (4) automation components that are written for the specific platform.
Because these dependencies are shared but not identical, the same brokerage account or data source may behave differently between MT4 and MT5. The practical question is not only whether you can install the software, but whether the whole chain—OS → platform → broker connection → data/symbols → automation runtime—works end to end.
Mechanics: what “compatibility” means in practice
Operating systems and installation
Compatibility begins with the operating system (for example, Windows-based setups versus other environments). Even when both platforms are broadly available for a given OS family, the exact installation method, update behavior, and runtime features can differ.
A useful assumption for verification is simple: if you cannot run the platform on your target device environment, there is nothing else to “match.”
Broker server access and account linkage
Both MT4 and MT5 typically require connection to a broker-provided trading server. Compatibility depends on whether the broker supports the platform for that account, and whether the platform can authenticate and maintain an active session.
A material failure mode here is mismatch: the platform may install successfully, but the broker account may not be usable in that specific platform environment (for example, due to account type differences or server-side settings).
Data feeds and tradable instruments
Market data and symbol availability depend heavily on the broker’s setup. “Compatible with” in this area means the broker provides the instruments, pricing updates, and history the platform expects.
Also separate concepts: the platform can be “compatible,” yet the data might still be incomplete for a given use case (for example, limited history depth, different contract/symbol naming, or differing update cadence). That changes how you interpret backtests and how strategies behave.
Automation and language/runtime constraints
Automation works only when the automation code is written for the platform’s expected language and execution model.
A common limitation is that automation made for MT4 cannot be assumed to run in MT5 without adaptation. Likewise, if the automation requires specific account permissions or runtime conditions, it may load but not execute as expected once connected.
Limitations and risks (what can go wrong)
- Installation success is not full compatibility. The most important breakpoints are the broker connection and data/symbol availability.
- Platform differences can change behavior. Execution timing, backtesting assumptions, and how trades are handled can differ between MT4 and MT5 even with similar broker settings.
- Automation can fail silently. An expert/automation component may compile or attach but refuse to trade due to permissions, missing data, or logic that assumes different platform capabilities.
- Verification based on past history is limited. Historical relationships do not guarantee future results, especially when costs (spreads/fees), execution quality, or volatility regimes change.
Verification and next question
To verify MT4 vs MT5 compatibility without relying on assumptions, check these items in order: (1) whether the platform runs on your target operating system and device, (2) whether your broker account can connect to that platform’s server, (3) whether the instruments and pricing feed match what you need (names, availability, and history depth), and (4) whether your automation components are built for that exact platform and can execute under the connected account.
If you want, share the device OS and the broker/account type (no account numbers needed). Then the remaining question becomes: which part of the chain is the likely constraint—installation environment, broker server access, data/symbol coverage, or automation language/runtime.