An MT4 signal copier with its status stated plainly

Same protocol as MT5, MT4-shaped execution

Everything in the local protocol applies to MT4 unchanged: the same routes, the same bearer-token authentication, the same session lifetime, the same duplicate guard, and both transports.

What differs is the trading model, not the protocol. There is no CTrade in MQL4, so a hand-rolled class drives OrderSend and family; there is one ticket space, so a pending order becomes a position under the same ticket and there are no deals; registration is always hedging with DEMO or REAL account modes only; and MT4 reports its own ERR_* codes through a fresh category mapping, with connection and timeout failures held for reconciliation exactly as on MT5.

Broker quirks are handled before submission: send-then-modify where a broker rejects entry stops, bounded trade-context waits that serialize submission rather than retrying it, stop and freeze-level checks reported as readable reasons instead of bare codes, volumes rejected rather than rounded, and mandatory slippage defaulting to 3 points.

A partial close on MT4 replaces the ticket: the broker closes the original order and opens a new one for the remainder, so the desktop follows the remainder through ticket_lineage and later management follows the surviving position. Anything ambiguous is reported for reconciliation rather than guessed at. As everywhere, trade management acts only with per-channel consent, which is off by default.

And the privacy split is identical: message content never leaves your PC, while the cloud syncs only dashboard metadata such as trades and account snapshots.