When using certificates which are signed by a CA will WebSphere MQ support the digital certificate verification signed with RSA SHA256 per NIST standards ?
WebSphere MQ z/OS System SSL for certificate management and SSL connection negotiate so there are no specific requirements for the signature algorithm of certificates. If System SSL can process the certificate then it is supported with WebSphere MQ.
OA22451 documents new function for z/OS 1.8 with reference to the SHA-2 algorithm.
WebSphere MQ WMQ