皮匠和各位大虾: Details about 485 pending transfer h1B to new employer.

Thank you for your help first.

My 485 pending over 180 days. I have a new offer which require me to work for them ASAP. I have EAD.

Could I work for the new employer and then transfer my H1b after three month probation period?

If not
could I work for the new company after the company file H1B transfer online with confirmation notice from the website. Do you think I have to get a receipt notice through mail from USCIS first and then work for the new company?

Appreciate your inputs.