This question already has an answer here:
I am in the situation where I submitted an article 1 year and 4 months ago. I already asked to editors about the status nearly five months ago and they replied they are still waiting for the referee answer and that they were going to ask to expedite the process.
I didn’t receive other news since them, and I don’t know if it will be time to contact them again. Would it be considered impolite? What is your suggestion?