I’ve decided to stay abroad for a year (abroad starting August 1, 2020) and am considering taking the foreign earned income exclusion. If I decide to go that route, when should I have my employer stop withholding income tax?

My concern is that by April 15, 2021, I will not yet have been out of the country for 11 months.

Does that mean I can only claim the exemption, and get a refund, the following year (in 2022)? Or, in April 2021, can I say "I’m on track to be out of the country until July" and still take the exemption / have my employer stop withholding now?

What if I file for an extension and pay in October 2021, does that make a difference?

If the tax filing deadline is again pushed to July in 2021, would I then be in the clear to stop withholding now?

Edit

I’ll be using the physical presence test, not the bona fide resident test (I won’t be staying in a single country). The employer is US based (which still counts as foreign earned income): https://www.irs.gov/individuals/international-taxpayers/foreign-earned-income-exclusion-what-is-foreign-earned-income