There are some differences in the programming interfaces for the new devices. One of the main ones is that customers can now choose to unlock and lock the JTAG with a password instead of having to use the JTAG fuse blow to secure IP. This makes it easier to update firmware with less pins than having to use a Boot Strap Loader. Also, the BSL on the device is hard coded into ROM, cannot be modified, and can only be accessed through the hardware UART.