current BK app version 2.4 in app store requires to run at IOS 5.0 or above. we suggest all members to upgrade to lastest IOS version before upgrade/downloading 2.4 version. For those whom doesn't what to upgrade their IOS then should wait until the next version 2.4.1 for compatibility fixes. Targeted date is the end of August or first week of September, depends on Apple's reviewing progress.