There seems to be a simple solution...-
https://www.ixsystems.com/community/threads/changes-in-smb-for-11-1u5-to-11-1u6.69442/#post-477577
Go into your SMB configuration and try pasting the following into the "Auxiliary Parameters" field. Doing so will add that parameter to the SMB.conf.
I haven't tried it myself yet.
I don't think changing numerous clients to comply with some arbitrary change to a server is particularly good practice if things had been working fairly reasonably up to this point.