The U.S. Department of State has on December 29, 2020 temporarily extended the eligibility for Interview Waivers to protect people during the Covid-19 pandemic.
Originally, certain nonimmigrant visa applicants were eligible for interview waiver if the previous visa in the same category held by the applicant expired within the last 12 months. This was temporarily extended until December 31, 2020; permitting nonimmigrant visa applicants whose visa expired within the last 24 months to qualify for the interview waiver.
The new notification further extends this temporary relief until March 31, 2021. The relevant notification can be found here.