Starting with the September 2020 mid-month pay period through the end of the year, most service members will see paychecks increase by about 6.2%, but will have to pay back all of that money through larger withholdings from Jan. 1 through April 2021. Military retirees will not be affected. Service members and DoD civilians "are not eligible to opt-out of the deferral if their Social Security wages fall within the stated limits. The deferral will happen automatically." For more information see these links:


https://www.military.com/daily-news/2020/09/08/troops-dod-civilians-wont-be-able-opt-out-of-payroll-tax-deferral-plan.html


https://www.military.com/money/personal-finance/2020/09/02/4-ways-stop-payroll-tax-cut-lowering-your-2021-paycheck.html