VMware certifications are no longer titled after product versions, so if you completed the requirements for your certification this year you already hold the latest certification VCP-NV 2020.
Until the NSX-T 2.4 exam is retired, VCP-NV 2020 can be achieved by passing either the 2.4 exam or the 3.0 exam:
There's nothing to stop you taking the 3.0 exam now, but passing it won't award you a new certification if you're already a VCP-NV 2020.
There won't be a 2.4-3.0 upgrade exam, for the reasons above.
You'll see on the VCAP pages that it's the VCP year which counts nowadays too - so if you're VCP-NV 2019 or VCP-NV 2020 you meet that requirement for VCAPs.
Fantastic...thank you so much.