My H1B VISA is going to expire soon. I have not travelled yet. I am planning to switch company soon. Suppose If I don’t travel at all and VISA gets expired then If my new employer files for VISA extension/modification may be after 6 months or 1 or 2 year of expiry of my VISA , will there be any issue or any other process involved ? Is travelling on current H1B visa mandatory for filing extension/modification/transfer ?