: For the most accurate and detailed information, I recommend checking Cisco's official website. They have product pages and support sections where you can find software details.
c800-universalk9-mz.SPA.159-3.M10.bin is the specific Cisco IOS software image for the Cisco 800 Series Integrated Services Routers (ISR) running release 15.9(3)M10 c800universalk9mzspa1593m10bin better
Use show version and show flash to check available space. : For the most accurate and detailed information,
The universalk9 feature set supports advanced encryption, VPN technologies (FlexVPN, DMVPN, GETVPN), and secure management (SSHv2, SNMPv3). Compared to an ipbasek9 image, universalk9 is better for secure branch or remote site deployments. VPN technologies (FlexVPN