Is it permissible to borrow money to pay Zakat al-Fitr?

Zakat al-Fitr is only obligatory for those who are capable of paying it at the time it becomes due. This is defined as what remains of one's sustenance and the sustenance of those one is obligated to support, after sunset on the last day of Ramadan. For someone who is not capable of paying it, it is not obligatory for them. However, it is permissible for them to borrow money to pay it, and they will be rewarded for doing so.