C800universalk9mzspa1583m9bin Work

The file is ZIP-compressed to save space on the router's limited flash memory. When the router boots, it "unpacks" itself into the memory. 4. The Security Badge: SPA

From the naming:

: Note that starting with version 15.6(3)M, certain weak ciphers (like dhe-aes-256-cbc-sha ) were removed for improved security. to your router's flash memory? Cross Platform Release Notes for Cisco IOS Release 15.8(3)M c800universalk9mzspa1583m9bin work