Hey,

New post up from Sarah Chen on the Cisco Catalyst 9000 upgrade lifecycle — everything you need to know before touching production Cat9K switches.

Catalyst 9000 IOS-XE Software Upgrades: Bundle Mode vs Install Mode, ISSU, and SMU Patching https://ignaonline.com/catalyst-9000-ios-xe-upgrade-issu-smu-install-mode/

What's covered: - Bundle Mode vs Install Mode: why Install Mode matters and how to convert - Standard install workflow (add → activate → commit) with real IOS-XE 17.x CLI output - SMU (Software Maintenance Update) patching — fix CVEs without a full image upgrade - ISSU on Cat9300 StackWise stacks — near-hitless upgrades with sub-30-second switchover - Golden image management and EEM-based version compliance alerting - Common gotchas: flash space, stale boot variables, ISSU compatibility matrix

Full CLI examples throughout. Good reference to bookmark before your next maintenance window.

— ignaonline.com