A mature, stable, and highly recommended "Long Lived" release for the Cisco 800 series. It is arguably the most reliable choice for branch offices and remote workers still utilizing this hardware generation before the End-of-Life (EOL) transition.

Look for DRAM – needs to be 262144 KB (256 MB) or more.

Understanding the Cisco IOS Image: c800-universalk9-mz.SPA.158-3.M9.bin