It includes cumulative fixes for "caveats" (bugs) identified in previous 15.9(3)M releases, such as memory leaks or process crashes in specific routing protocols.
Once the 90MB file was tucked into the router's flash memory, the real tension began. Elias adjusted the boot system priority and issued the command: reload . c800universalk9mzspa1593m10bin better
The Cisco IOS image c800-universalk9-mz.SPA.159-3.M10.bin (Release 15.9(3)M10) is generally a "better" or more stable choice than its successor, 15.9(3)M11 , because the later version has a known critical bug ( CSCwp13843 It includes cumulative fixes for "caveats" (bugs) identified