You followed the step-by-step WP-CLI procedure from W4, the terminal printed "Success: Core updated successfully," and the session is over. Stopping there is the most common place for post-upgrade problems to slip through undetected.
WP-CLI's "success" means the core files were replaced. It doesn't mean the site is working. Whether the database migration completed cleanly, whether plugins are compatible with the new core, whether forms submit, whether carts process — these require human verification after the command finishes.
This checklist pairs with the pre-upgrade checklist from W1. Where W4 covers what to run, this covers what to check when the running is done.
Why "updated successfully" isn't enough
A successful WP-CLI command doesn't guarantee:
