Think of MQ4 as a recipe written in plain English, and EX4 as the baked cake. You can share the cake (EX4) with customers, but you usually keep the recipe (MQ4) private.
: These are "Source Code" files written in MetaQuotes Language 4 . They are human-readable, meaning you can open them in an editor to see and change the logic of an Expert Advisor (EA), indicator, or script . mq4 to ex4
Embed a date check in your code. After a certain date, the EA stops trading. This forces users to renew licenses. Think of MQ4 as a recipe written in
Split your EA into multiple MQ4 files. Compile the core logic into an EX4 and call it from a shell EA. This adds another layer of complexity. mq4 to ex4