about PKCS11 document
From release note of 9.16.22, there is following line, The use of native PKCS#11 for Public-Key Cryptography in BIND 9 has been deprecated in favor of the engine_pkcs11 OpenSSL engine from the OpenSC project.
but in section 5.11.2 Native PKCS#11 of Bv9ARM(9.16.22), there is one opposite meaning line, (Note: Eventually, when more HSMs become capable of supporting native PKCS#11, it is expected that OpenSSL-based PKCS#11 will be deprecated.)
I guess the latter(5.11.2) should be outdated. But not too sure.