We have noticed that nearly every single iPhone user who has recently upgraded to 4.3.0 has had their notification settings set to off for both notification options.
This is clearly a result of an error regarding default notification settings for the new version after the upgrade, which will be investigated right away (and a fix released).
As a result, in the case of both notifications being "off", we have reset both to being "on".
In cases where it is clear a notification preference has been set by the player, no change was made, but apologies to the few users who have actually turned off both notifications by choice - you will need to reset your preferences possibly more than once until a fix is released.