On your Wazuh-Manager you can list your outdated agents via the command /var/ossec/bin/agent_upgrade -l.
You will get a list of outdated agents and their IDs. Just pick an ID, e.g. 004 and execute /var/ossec/bin/agent_upgrade -a 004.
After the upgrade is finished it wont get listed when typing again /var/ossec/bin/agent_upgrade -l
Fine more information here: https://documentation.wazuh.com/current/user-manual/agents/remote-upgrading/upgrading-agent.html