I Wanna Reset My iPhone5S,But It's Disabled.How Can I Solve This Problem?

I haven't used my iPhone 5S for a long time. Yesterday, I took it out from my drawer only found the iPhone was disabled. How can I fix it? Or, where can I download the iOS 7 firmware, which is compatible with my iPhone? If I update it to the newest version, the iPhone will run like an English patient. Is there anyone who can help me?

Thank you very much.

Mar. 11th, 2018