Due to the way Jira Cloud is architected, not everyone gets new features all at once. The changes are deployed in phases across everyone's Jira instances.
I'm not sure what you're referring to specifically with the More button - a screenshot would help! We can check your particular instance to see if a feature has been deployed yet if it's something still in the process of rolling out.
As an aside, you can also check the Next-Gen roadmap to see what's recently shipped and what will be coming soon: https://www.atlassian.com/roadmap/jira-software