Introduction:
Keeping your network infrastructure up to date is essential for maintaining performance, security, and stability. The Cisco Catalyst 3850 series is widely deployed in enterprise networks, and upgrading to the latest recommended software ensures you have the latest bug fixes, features, and security patches. This detailed guide walks you through the process of upgrading a WS-3850-24T-L from IOS XE 16.09.08 to 16.12.13 in Install Mode — from preparation to verification.
Prerequisites
- Access
- Console access or SSH access to the switch
- Privileged EXEC mode access (
enable)
- Checks
- Model:
WS-3850-24T-L - Current version:
cat3k_caa-universalk9.16.09.08.SPA.bin - Target version:
cat3k_caa-universalk9.16.12.13.SPA.bin - Recommended software downloaded from Cisco portal
- Verify boot system and available flash space
- Model:
- Tools
- Transfer method: TFTP (
192.168.1.10), SCP, or USB - MD5 checksum for target image:
aa277fa2cf9bcd8519ac1f567a7a090b
- Transfer method: TFTP (
- Backup
- Save running configuration locally and remotely
- Run and save outputs of important verification commands (e.g.,
show version,show boot,show inventory) to compare after upgrade
Upgrade Procedure
1. Verify Current Model & Version
show version
2. Check Boot System & Free Flash Space
show boot dir flash:
3. Save Running Configuration
copy running-config startup-config copy running-config tftp:
4. Remove Unnecessary Files (If Needed)
request platform software package clean switch all
To Manually delete the directory use
delete /force /recursive flash:/old_version_directory
5. Transfer New Image to Flash
copy tftp://192.168.1.10/cat3k_caa-universalk9.16.12.13.SPA.bin flash:
6. Verify Image in Flash
dir flash:
7. Verify MD5 Checksum
verify /md5 flash:cat3k_caa-universalk9.16.12.13.SPA.bin
8. Confirm Boot Variables
show boot system
9. Install the New Image
request platform software package install switch all file flash:cat3k_caa-universalk9.16.12.13.SPA.bin
Use below command for stacks switches
request platform software package install switch all file flash:cat3k_caa-universalk9.16.12.13.SPA.bin auto-copy
10. Save Configuration & Reload
write memory reload
11. Post-Upgrade Verification
show version show boot
12. Optional Cleanup
request platform software package clean switch all
Conclusion
By following these steps, you can smoothly upgrade your Cisco Catalyst 3850 switch while minimizing downtime and ensuring system stability. Always verify prerequisites, perform backups, and check MD5 integrity before installation to avoid potential issues. Regular upgrades not only fix bugs and patch vulnerabilities but also ensure compatibility with modern networking features — keeping your network secure and efficient.