I want to upgrade a Cisco 2621 router IOS. The current IOS in flash is c2600-jk8o3s-mz.122-17.bin. The closest latest version I could find is c2600-ik9o3s3-mz.123-22.bin. What is the difference between the jk and the ik and the s and s3 in the IOS names? I want to make sure I am using the correct IOS. The router has IP Routing/Firewall FS/ and VPN abilities. Any help would be greatly appreciated.
I have this problem too.