Korean Air will extend the expiration date of mileage expiring at the end of 2020 by one year, as passenger travel has been greatly affected by reduced routes and travel restrictions due to COVID-19.

Mileage accrued between January 1, 2010 and December 31, 2010(*) Current
Expires on January 1, 2021(Based on KST)
New Expires on January 1, 2022(Based on KST)

(*) Mileage accrued through Korean Air and its partner airlines: Based on the date of travel
      Mileage accrued through partner companies: Based on the date of accrual

You may check the extended validity on the website after July 13th, 2020.