T5220 support ended with Solaris 11.3.
See
End of Feature Notices for Oracle Solaris 11
> End of Features (EOF) for Oracle Solaris 11.4
--> SPARC: Legacy System Support
----> Support for the following legacy systems is no longer available, and you will not be able to upgrade these systems to Oracle Solaris 11.4.
------> Platforms based on UltraSPARC T2 CPUs: Sun SPARC Enterprise T5120 and T5220, Sun Blade T6230, Netra CP3260, and Netra T5220