You can go to the Options|about to find your exact phone model. Then you can select that phone from the device listing on this forum and then check the sticky post at the top of that forum download the OS upgrade and follow the instructions to do the upgrade.
From the 8330 and 8330m "Latest OS" threads stickied at the top of this forum:
How to determine if you have an ESN or MEID based device.
From the main menu, select Options, then select Status.
ESN devices - On the Status screen you will see ESN on the display
MEID devices xxx8211; On the Status screen you will see MEID on the display.
NOTE xxx8211; You cannot install ESN-based software on a MEID device, nor can you install MEID-based software on an ESN device. They are NOT interchangeable.