The tracks are all individual, so to upgrade to VCDX 2024, you will need to take the VCAP Design 2024 exam in that track. For example, if you are a VCDX-DCV 2021, regardless of how many other VCDXs you hold, you will need to pass the VCAP-DCV Design 2024 exam to upgrade to VCDX-DCV 2024.