No and maybe.

Child support payments are neither deductible by the payer nor taxable to the recipient. When you calculate your gross income to see if you're required to file a tax return, don't include child support payments received.

Under divorce or separation instruments executed on or before December 31, 2018, alimony payments are deductible by the payer and taxable to the recipient. When you calculate your gross income to see if you’re required to file a tax return, you should include alimony payments received under such an instrument.

However, under divorce or separation instruments executed after December 31, 2018, and under certain instruments executed on or before December 31, 2018 but later modified, if the modification expressly states the repeal of the deduction for alimony applies to the modification, alimony payments are neither deductible by the payer nor taxable to the recipient. When you calculate your gross income to see if you’re required to file a tax return, don’t include alimony payments received under such an instrument.