Hi,I need to create this network 192.168.248.0 255.255.254.0 on my asa.when i created it with ASDM, by default it created with the mask 255.255.255.0,How can i change that default mask to the correct i need ? (255.255.254.0)

Hi, I have one ASA 5540 with IOS 7 and asdm 5i want to upgrade the ios to 8 and the asdm to 6. recently, i upgraded the ios to 8, but the asdm didn't work.How to do these upgrade ?Thanks