Planning upgrade of CA Access Gateway (SPS), what's the meaning of the warning from documentation (1)?
"an OpenSSL 3.0 environment?"
from
"You must have an OpenSSL 3.0 environment where you can run the compatibility commands to validate the suitability of your certificates and their keys in Access Gateway after the upgrade."
It's mainly referred to a standalone and test machine with the CA Access Gateway (SPS) 12.9 only installed.
Check the compatibility of the keys and certificates with this CA Access Gateway (SPS).
If incompatibilities are found, recreate the certificates using OpenSSL 3.
Note that as temporary installation of validation tools, installation of the CA Access Gateway (SPS) 12.9 on the same machine to the Policy Server 12.9 might be useful.
Remember that the CA Access Gateway (SPS) is a standalone server and it should not be installed and run on the same box as the Policy Server in Production.