The following behavioral changes should be noted for anyone upgrading from earlier builds of FreeNAS (any version) to 9.3-RELEASE 1. This build now uses ZFS, the GRUB boot loader, and GPT partition labels for all boot media. This is a significant change from earlier releases and may cause interoperability issues with older hardware / BIOSes. In the event of a failed upgrade, one possible remedy may be to back up your configuration database and try a fresh install using the 9.3-RELEASE ISO installation image (which can also be used from USB devices). 2. Because it is now possible to accumulate an arbitrary number of ZFS boot environments, the recommended default installation media size is now 8GB. For maximum reliability, at least a pair of 8GB devices is suggested. Smaller (4GB) media will still work, but space will be very tight and the number of boot environments will need to be managed very carefully lest future update attempts fail due to lack of space. 3. Authenticating via LDAP now requires that the connection to the LDAP server be SSL/TLS. This prevents account passwords from being sent in clear-text but may be an unexpected change in behavior for users upgrading from older releases of FreeNAS. 4. The CTL LUN serial number generator has been changed to match the previous istgt (userland iSCSI) behavior for compatibility. This was done after the 9.3-BETA, so those who switched to the Experimental iSCSI target in 9.2.1.x or used iSCSI in 9.3-BETA will see a serial number change.