Install Junos OS Software Package
You can use this procedure to upgrade Junos OS on the device with a single Routing Engine.
Junos OS is delivered in signed packages that contain digital signatures to ensure the Juniper Networks software is running. When installing the software packages, Junos OS validates the signatures and the public key certificates used to digitally sign the software packages. If the signature or certificate is found to be invalid (for example, when the certificate validity period has expired or cannot be verified against the root CA stored in the Junos OS internal store), the installation process fails.
To install software upgrades on your device with a single Routing Engine: