I have some questions on when to get my H1-B extension done. Below are the details.
? My Cap H1-B was approved in 2016 and is valid until August 2019. But my H1-B amendment is valid only until Sept 2018.
? The other thing is I traveled out of USA after my amendment was approved and while coming back, my passport was stamped with August 2019 validity. Since my passport and latest I-94 say August 2019.

1. Do I need to get my extension done by Aug 2019 or Sept 2018 (as per amendment date)?
2. Post Sept 2018, can I work at locations mentioned in original H1B until August 2019 without doing extension?