FrontPanel SDK v5.2.5, which includes FrontPanel HDL sources encrypted with 2021 Vivado public keys, is now available through the downloads page:
https://pins.opalkelly.com/downloads
You must use Vivado 2021 or later with these 2021 key encrypted sources. The previous sources, which were encrypted with earlier public keys, are still provided in the installation and must be used with that year’s Vivado or later. Although, starting with Vivado 2021.1, sources encrypted with keys older than 5 years are not supported.