I-94 record

[kc10]

Hi,
I received my H-1B extension in March 2018 with I-94 validity from August 2018 to August 2021 at the bottom of my I797.

In July 2018, I traveled to India and on arrival I received an I-94 with an expiry date December 2020.

Does anyone know what is the applicable I-94 for my case now?

Is it the I-94 that I received with I-797 with validity start date in August or the I-94 issued by CBP at the airport in July?

[Visa.Seeker]

The latest issued I-94 overrides the previous ones. If your Visa is valid until August 2021, you should renew your I-94 by stepping out of US and stepping back in. People on west coast usually travel to Mexico for that, while North East coast folks prefer Canada.