Pixelum firmware
Download the newest firmware, then install it from your panel's web page: open the page, go to Firmware update, choose the file and press Install update.
Normal ESP32 (DevKit)
Download firmware-esp32.bin
Download firmware-esp32.bin
ESP32-S3
Download firmware-s3.bin
Download firmware-s3.bin
Do not unplug the panel while it installs. If the new version does not start, the panel goes back to the old one by itself.