To comply with USCIS regualtions, we will soon inform USCIS of your termination . We very much hope this will not adversely affect your immigration situation, but we have been advised by counsel that it is nessessary for us to contact USCIS about this"
What does the company trying to say?
-Immigration law requires the employer has to report that the employee with H1 status is laid off to USCIS and require USCIS to terminate the H1 status of the employee.
Will they withdraw my approved I-140?
-Not really, up to your current employer. Immigration law does not require the employer to cancel/withdraw the I-140 for the employee who is laid off.