Stopping IRS junk mail

[cattleherder]

A minor inconvenience to resolve, maybe the American folks here may offer some advice.

I lived in the US on a working visa for a couple of years before moving to Singapore in late 2017. Being law-obedient and stuff, I made it a point to pay my US taxes for 2017 (even though it was a highway-robbery kind of amount because of another regulation XYZ, whatever). I also updated IRS on my whereabouts in Singapore to pay that. So far so good.

I am now a non-resident alien from the US taxation perspective, so 2018 and subsequent years are none of their business. However, they keep sending their mail. Nothing important or threatening, but more like, Captain Obvious reporting for duty. "Regulation E disclosure - What to do about an error or problem?"

The trouble is, I moved to a different apartment, and the nice lady who owns my previous apartment was worried and thought it was something important. It is also not her job to keep and forward me my mail. But looks like she'll keep receiving this junk.

It's the IRS, clearly. There seems to be no way to "unsubscribe from junk mail". It would be slightly annoying to have to update a taxation authority in a foreign country on my whereabouts until the end of my life, but I'm OK doing it a couple of times, because I feel uncomfortable forcing other people do my chores.

The question is, how? There seem to be some kind of forms you have to fill out, most likely, without the electronic option. Is there an easier way than to rent a horse and ride to the IRS headquarters and provide them an envelope with a red wax seal and a form No. 12345 inside?