Let’s walk through a high-level example. Assume you have the MQ4 source of a moving average crossover EA.
For the vast majority of traders who do not have programming skills, MetaQuotes (the developer of MetaTrader) has provided a built-in solution. How To Use Ex4 File In Mt5
To use an MQ4 file in MT5 reliably, it must be "ported" to MQL5. Let’s walk through a high-level example