I did a H1 transfer from company A to B and the current petition with company B is valid till DEC 2021.
Correction: There is no validity for a petition, An approval only would have the validity. You mean by your Company B H1 Petition approval is valid till Dec 2021?
H4 transfer did happened but the expiry date was till 31st Dec 2018, And while we did for for my H1B extension, my family H4 not happend since my dependents were in India.
Question: Do you mean by the Stamped H4 validity was till Dec 31st?
(Side note: You should have gotten the H4 also extended along with your Company B H1 petition)
Me and my dependents have valid visa from company A till 2019 June.
Question: When you said valid visa means is it Company A approval OR stamped visa ?
I need to travel India a month for vacation.
Can i travel back with my old stamped visa from company A along with my family?
Ans: Travel means going out of United States? If so, you dont need to care about any visa as you are leaving USA. But if you want to enter into United states, you MUST have a valid stamping on your passport, if not you will not be allowed to enter into United States.
If not 1 , What about my family H4 visa ? Are they required to file I-539 petition ? Or Only Visa stamping with new company i.e B is enough to travel ?
Ans: You and your family should go together for stamping using your Company B Approval. Your spouse’s existing H4 visa already expired and his/her stamping is also expired (as it was initially based on Company A’s H1 Approval, which is not valid now).