update carrier settings please advise!

[ibiggy]

Hi need some advice please, i have been asked to update to 4.0.1, in itunes 9.2, i have read and for obvious reasons i declined, and immediately after i cancel i get another itunes window saying -

"An update to the carrier settings for your phone is available, would you like to download it now"?

There are then three options "learn more" "download update" or "cancel"

I have an iphone 3gs 16g, on ios 4.0 (legit) on an mc model, i bought the phone legitimately through "chitter chatter" a third party company for T-mobile in UK, i am also being asked via my iphone
"New settings are available for your iphone. Would you like to update them now? with a "not now" option or "update" option, can someone please advise if this is ok or not, i am unsure and don't want to mess my iphone up, i am a stickler for "if it ain't broke then don't fix it"
Any help is much appreciated
Regards
ibiggy

[skiptowncat]

If you don't need an unlock it
should be fine to update carrier
settings. (I think )

[adp]

If you're in T-mobile UK and you don't rely on an unlock to use your phone then yes, update your carrier settings

[ibiggy]

Have updated carrier and all is fine
Kind regards
Ibiggy