Source code
MQL4 to MQL5: what changes when porting an EA
Porting an EA is a translation of behaviour between platform models. A clean plan starts with what the strategy must do, then maps each requirement to the target platform.
Write a behaviour map first
Describe entry conditions, exit conditions, sizing, position ownership and session rules. Include what should happen after a restart or rejected request. This short specification keeps the port focused on observable behaviour rather than a line-for-line resemblance between two files.
Adapt data and indicator access
MQL5 uses indicator handles and buffer access for common indicator workflows. Check bar shifts, array indexing, history readiness and timeframe selection. A formula can look familiar while reading a different candle, which is enough to change the strategy.
Adapt the trading model
Review orders, deals and positions separately. Decide which account modes the new EA supports and how it identifies its own positions. Replace assumptions about order selection and closing with explicit MQL5 operations; merely renaming the source extension does not perform that work.
Validate in small stages
- Compile a minimal data and indicator layer.
- Check a few known signal timestamps.
- Verify sizing and ownership with simple cases.
- Compare entries and exits over a fixed test interval.
- Document environmental differences instead of hiding them inside code changes.
Make it yours with MQLume
MQLume offers editable MQL5 projects for traders who want a direct starting point on MT5. Browse Quantum Commander MT5 or explore the source and executable file guide.