DFU bootloader code size

[Webmobi]

Our code is 21k excluding soft-device,as per the example 15k should be the max size limit of code to update FOTA. Is it possible to make changes in DFU bootloader so that i can transfer FOTA?

[Webmobi]

My code size is 21.6K, i want to transfer over air is it possible ? i am planning to alter FOTA example