root@QFX5200> request system software add /var/tmp/jinstall-host-qfx-5e-x86-64-21.4R3-S3.4-secure-signed.tgz no-validate no-copy 
Verified jinstall-host-qfx-5e-x86-64-21.4R3-S3.4-secure-signed signed by PackageProductionECP256_2023 method ECDSA256+SHA256

Message from syslogd@QFX5200 at Jan  1 16:50:58  ...

Forcing the Host Upgrade for Non Issu updates...
Pushing Junos image package to the host...
Installing /var/tmp/install-media-qfx-5e-junos-21.4R3-S3.4-secure.tgz
Extracting the package ...
...
upgrade_platform: Checking input /var/tmp/jinstall-qfx-5e-junos-21.4R3-S3.4-secure-linux.tgz ...
upgrade_platform: Input package /var/tmp/jinstall-qfx-5e-junos-21.4R3-S3.4-secure-linux.tgz is valid.
...
upgrade_platform: Staging of /var/tmp/jinstall-qfx-5e-junos-21.4R3-S3.4-secure-linux.tgz completed
upgrade_platform: System need *REBOOT* to complete the upgrade
upgrade_platform: Run upgrade_platform with option -r | --rollback to rollback the upgrade

Host OS upgrade staged. Reboot the system to complete installation!