Requote (138) versus price changed (135): different messages, different risks

[Amanhasnoname]

MT4 reports two similar errors. Error 138 means the requested price is no longer available and the server offers a new one. Error 135 means the price changed and the order was rejected outright, with no new offer attached.

The practical difference lies in the retry logic. After a 138, the platform often supplies the new quote, and an EA can decide whether to accept it. After a 135, the EA needs to refresh rates and recalculate.

Both signal that the market moved between decision and arrival. Their frequency is a direct measure of how much latency hurts the strategy. A system that sees these errors on more than a few percent of orders has a latency or execution-mode problem.

Distinguishing the two in analysis helps. A high 138 count suggests instant execution with tight tolerance, while 135 often points to pending order activation or modification timing.

Logging the error code, the requested price, and the price at the moment of failure turns a vague annoyance into data.

What share of order attempts end in 135 or 138 on the account in use?