Companion thus can’t reach the download server anymore. This is caused by the combination of the expiration of a Let’s Encrypt root certificate and the fact that the OpenSSL library that has been bundled with the Windows version of Companion is too old to support the transition method that Let’s Encrypt has used. Since Sept 30th, 2021 OpenTX Companion for Windows is not able to check for updates / download them or download firmware anymore.
