Otherwise, the bootloader will be destroyed! Unless you have a RBLink to fix the bootloader yourself.
If you have updated your Duo to this version, you MUST NOT downgrade the system firmware version. the du-util command with -a 1 option) via DFU mode will result failure, since the bootloader updated by system firmware v0.3.2 or above depends on DCT related functions those are implemented in system firmware v0.3.2 or above only. And please note that if you downgrade the system firmware to v0.3.1 or below, updating DCT(i.e. By upgrading the system firmware from v0.3.1 (or below) to v0.3.2 (or above), the bootloader will be upgraded automatically. This version can NOT be downgraded to v0.2.4 or below! Otherwise, the new bootloader will be destroyed by old system firmware. This release is exactly based on the release v0.7.0-rc.7 of upstream. Anyway, the Duo firmware which version is above 0.3.3 will mostly functions as a Particle Photon, except that the Duo implements the BLE functionality and BLE setup. Particle develop branch, and some of the features will be deprecated, such as local OTA over TCP/IP, Arduino uploading and WICED application uploading, etc (Check PR: particle-iot#1505).
Since the firmware for the Duo will be merged to the upstream branch, i.e. This release hopefully is the LAST release for backward compatible with 0.3.2 or below!
