ios 7 willsupport iphone 4?

You can look this up yourself on Apples website.

http://www.apple.com/ios/ios7/features/

Yes it will be able to support it.

iOS 7 will be compatible with:

• iPhone 4*
• iPhone 4S
• iPhone 5

• iPod touch 5th generation 16GB
• iPod touch 5th generation 32GB/64GB

• iPad 2
• iPad with Retina Display
• iPad mini