The new rates are in effect from Oct. 1, 2021, to Sept. 30, 2022. Specifically, they are the special per-diem rates, including the transportation industry meal and incidental expenses rates; the rate for the incidental-expenses-only deduction; and the rates and list of high-cost localities...
For tax years through 2017, use IRS Form 2106 if you itemize deductions for non-reimbursed work-related expenses such as travel, meals, entertainment or transportation.