how i can build app in 2g phone using 3gs frameworks

I am developing one application which need scanning component, I have application ready but when I build it in 2g phone with os version 3.1.3, application gives me error. I have weak linked those framework which are not in 2g. ERROR: Not Enough Frames In Stack 开发者_运维问答Do advice thanks in advance.

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In such cases you have 2 options:

1. Always check existence of such API call by probing with respondToSelector: message
2. Check iOS version level by calling [UIDevice currentDevice].systemVersion and avoid incompatible calls by using good old if...else... statements