Microsoft stated the end possibilities of the cross-signed drivers. Blocking starts to operate since July 1, 2021 and will actually make impossible release of new drivers for operating systems Windows 7, Windows 8, Windows 8.1, Windows Server 2012 R2.
For developers who will release drivers for named above systems, there was a unique option of passage of testing HLK/WHQL. However features of this testing are that not all drivers for it are supposed. Among supposed not all can pass this check.
All drivers for Windows should have the digital signature that they could be established. Earlier it became through cross-signed process for old versions Windows in which the package of drivers subscribes the signed certificate of code signed certificate and cross-certificate. One can get these certificates from the intermediary by certification. It should be one of the confirmed one in Microsoft trusts.