H1b petition approved and visa stamped and still in india, can I apply for transfer?

H1b petition approved and visa stamped and still in india, can I apply for transfer?

Visa and approval is till mid 2017.

Can I apply for H1b transfer Cap extempt and till what time?

Another employer can file a cap-exempt petition for you within next 6 years. If original H-1 petition start date is Oct 1, 2015; then they can apply for it until Sep 30, 2021