Master Sketch on Farhan’s Github: https://github.com/afarhan/ubitx
Updated Sketch (for uBitx 4 but works on v3 also): https://github.com/afarhan/ubitx4
CEC Firmware from KD8CEC (works on all versions of the uBitx): V1.2000 Firmware: http://www.hamskey.com/2019/04/release-cec-firmware-v1200-for-ubitx.html (also links to uBitx Manager).
CEC Firmware V1.1 (includes Nextion LCD display): http://www.hamskey.com/2018/09/ubitx-firmware-cec-version-11-release.html
CEC guide to upgrading firmware: http://www.hamskey.com/2018/01/how-to-upgrade-ubitx-firmware.html