Before updating, you must identify your existing firmware. Unfortunately, the VG421WDV2 does not have a "display firmware version" command over I2C/SPI by default. You need to use one of these methods:
If it is a different brand (like Samsung, Netgear, or a specific dashcam), I can provide much more detailed specs on what that specific 2021 update changed. vg421wdv2 firmware 2021