The Rural Broadband Auctions Task Force has announced the opening of an optional certification window for eligible telecommunications carriers (ETCs) to certify as to the usage of their legacy high-cost support for mobile services. In conjunction with the 5G Fund, the FCC is requiring legacy high-cost ETCs to use their support for mobile services on 5G deployment. Specifically, the FCC adopted a rule requiring ETCs to use at least one-third of the support it receives in 2021 for 5G deployment — a portion that will increase to two-thirds in 2022. In 2023, ETCs will be required to spend the 100% of legacy high-cost support on 5G deployment services. This optional certification also will allow ETCs the flexibility to spend less than one-third of their support on 5G deployment in 2021 — with the requirement to make up any shortfall in 2022 in addition to the required two-thirds of their legacy support on 5G. The deadline to submit the optional certification is August 16, 2021.