@coldwarsoldier
Based on an internal discussion, AEM Forms SPNEGO SSO supports AES-256, and this switch shouldn't cause any issues.
Based on [0], I can see that type 18 is aes256-cts-hmac-sha1-96 so this encryption needs to be updated in the Kerberos config file otherwise these configurations will remain the same[1].
In case of any issues, enable the Debug logs on server, set the parameters -Djcsi.kerberos.debug=true, -Didm.spnego.debug=true and share the logs.
[0] - https://www.iana.org/assignments/kerberos-parameters/kerberos-parameters.xhtml
[1] - https://experienceleague.adobe.com/docs/experience-manager-64/forms/administrator-help/configure-use...