H1B Transfer - Is stamping Required?

Hi,

My H1B is expiring September 2018. However, I have extension approved till March 2021 and have received revised i797 and I94.

But now, I have employer B who is offering me a role and willing to transfer. Is it required to travel to India post Transfer approval for visa stamping or can i continue to stay in US post transfer petition approval?

Please suggest.