Where do i file my I-539 form? Starts with SRC for receipt for H1B?

My wife’s last approved H1B (I-797A) notice for I129 starts with LIN. But her current H1B extension filing receipt starts with SRC.

Where do i send my I-539 (H4 Extension form) for filing? Is it Dallas or Phoenix?


It is Phoenix. See below. Check Filing Addresses for Form I-539, Application to Extend/Change Nonimmigrant Status | USCIS