At http://www.zabbix.com/download.php agent binaries should be provided for Solaris 10 on the amd64 architecuture and Solaris 11 on the sparc architecture.

Currently we are able to run the Solaris 10 sparc binary on Solaris 11 sparc without noticing any issues so far, but a specific binary would seem safer.

Meanwhile the Solaris 11 amd64 binary appears to crash on Solaris 10 amd64, so this is of more concern. If needed I can provide the log output shortly before it crashes, but it would seem likely a binary compiled against Solaris 10 amd64 may not crash in this manner.