Some of the Apple ThunderBolt 2 docks have seen port changes and enclosure redesigns as they've been revised. Depending on whether the new docks are from Belkin, Matrox, ElGato, OWC or others - you may or may no longer have FireWire 800 or eSATA connectors. Higher power USB 3.0 ports may be offered to better support charging high-demand USB devices like Apple iPad tablets. Others have shifted from DVI to HDMI as the supported video out as vendors strive to match their docking hardware with the kinds of I/O interfaces most currently in demand.
At least SSD prices have gotten dirt cheap per Gigabyte in the past year helping to make these ultra-fast Mac backup solutions more affordable than before. For some; simply plugging a bare, off-the-shelf 2.5" SSD of your choosing into Seagate's Backup+ ThunderBolt drive dock is a workable and cheap TBolt backup option.
For a wide range of Mac compatible ThunderBolt Storage solutions visit www.thunderbolt-ssd.com for the fastest Apple backups ever!