Will my iPhone lock automaticlly again after I update it/restore it next time in the future?

Oh, I am sorry that I missed that!.

I just unlocked it with At&t's comfirmation. I bet this is an official unlocking. Is it?

At&t replied me this email:

"

Thank you for contacting AT&T Customer Care about unlocking your iPhone.

We have reviewed your request and confirmed that you are eligible to have the requested iPhone unlocked.

Please allow 24 hours upon receipt of this notification to complete the unlock.

To complete the unlock, simply:

1. Open iTunes on your Mac or PC and verify that you have Internet connectivity.
2. Ensure a SIM card is inserted into your iPhone.
3. Connect your iPhone using the dock connector to USB cable that came with your iPhone.
4. Backup and restore your iPhone using iTunes. For information on backup and restore, please visit http://support.apple.com/kb/HT1414.
5. After restoring, your iPhone will be unlocked.

Additional information on unlocking can be found at http://support.apple.com/kb/TS3198

For questions regarding AT&T's wireless service and iPhone, please visit the Phone/Device Learning Center.

We thank you for your continued business.

Sincerely,

AT&T Customer Care Team "