When upgrading Junos on QFX5000 series and EX4600/EX4650 switches, the "force-host" option should be used with the upgrade command (e.g. "request system software add /var/tmp/ <jinstall-package> " to ensure the Host OS is upgraded along with Junos.

The "force-host" option was not available for QFX5200 in Junos 15.1 and lower versions because it was not necessary since the Host OS would get installed automatically when upgrading Junos using an appropriate "jinstall" image file from Juniper's support site.

The "force-host" option is now available in newer Junos versions (18.x and higher). Both of the Junos upgrade and Host OS versions get upgraded on QFX5200 even without using the "force-host" option, however it is still recommended to use this option to ensure all Host OS related scripts/packages get upgraded along with Junos and Host OS applications.

Junos 15.1:

user@switch> show version    
localre:
--------------------------------------------------------------------------
Hostname: user@switch
Model: qfx5200-32c-32q
Junos: 15.1X53-D235.1
JUNOS OS Kernel 64-bit  [20180628.7473aae_builder_stable_10]
JUNOS OS libs [20180628.7473aae_builder_stable_10]
JUNOS OS runtime [20180628.7473aae_builder_stable_10]
JUNOS OS time zone information [20180628.7473aae_builder_stable_10]
JUNOS OS libs compat32 [20180628.7473aae_builder_stable_10]
JUNOS OS 32-bit compatibility [20180628.7473aae_builder_stable_10]
JUNOS py extensions [20180912.222750_builder_junos_151_x53_d235]
JUNOS py base [20180912.222750_builder_junos_151_x53_d235]
JUNOS OS vmguest [20180628.7473aae_builder_stable_10]
JUNOS OS crypto [20180628.7473aae_builder_stable_10]
JUNOS network stack and utilities [20180912.222750_builder_junos_151_x53_d235]
JUNOS libs compat32 [20180912.222750_builder_junos_151_x53_d235]
JUNOS runtime [20180912.222750_builder_junos_151_x53_d235]
JUNOS qfx runtime [20180912.222750_builder_junos_151_x53_d235]
JUNOS qfx platform support [20180912.222750_builder_junos_151_x53_d235]
JUNOS modules [20180912.222750_builder_junos_151_x53_d235]
JUNOS qfx modules [20180912.222750_builder_junos_151_x53_d235]
JUNOS libs [20180912.222750_builder_junos_151_x53_d235]
JUNOS Data Plane Crypto Support [20180912.222750_builder_junos_151_x53_d235]
JUNOS daemons [20180912.222750_builder_junos_151_x53_d235]
JUNOS qfx daemons [20180912.222750_builder_junos_151_x53_d235]
JUNOS Voice Services Container package [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services SSL [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services Stateful Firewall [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services RPM [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services PTSP Container package [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services NAT [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services Mobile Subscriber Service Container package [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services MobileNext Software package [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services LL-PDF Container package [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services Jflow Container package [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services IPSec [20180912.222750_builder_junos_151_x53_d235]
JUNOS IDP Services [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services HTTP Content Management package [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services Crypto [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services Captive Portal and Content Delivery Container package [20180912.222750_builder_junos_151_x53_d235]
JUNOS Border Gateway Function package [20180912.222750_builder_junos_151_x53_d235]
JUNOS AppId Services [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services Application Level Gateways [20180912.222750_builder_junos_151_x53_d235]
JUNOS Services AACL Container package [20180912.222750_builder_junos_151_x53_d235]
JUNOS SDN Software Suite [20180912.222750_builder_junos_151_x53_d235]
JUNOS Packet Forwarding Engine Support (DC-PFE) [20180912.222750_builder_junos_151_x53_d235]
JUNOS Packet Forwarding Engine Support (M/T Common) [20180912.222750_builder_junos_151_x53_d235]
JUNOS Online Documentation [20180912.222750_builder_junos_151_x53_d235]
JUNOS FIPS mode utilities [20180912.222750_builder_junos_151_x53_d235]
JUNOS Host Software [3.14.52-rt50-WR7.0.0.9_ovp:3.0.3]
JUNOS Host qfx-5e platform package [15.1X53-D235.1].    <-- Host OS version
JUNOS Host qfx-5e control-plane package [15.1X53-D235.1]
JUNOS Host qfx-5e data-plane package [15.1X53-D235.1]
JUNOS Host qfx-5e base package [15.1X53-D235.1]

{master:0}
user@switch> request system software add /var/tmp/jinstall-host-qfx-5e-15.1X53-D235.1-secure-domestic-signed.tgz ?
Possible completions:    <-- No "force-host" option for QFX5200
  <[Enter]>            Execute this command
  best-effort-load     Load succeeds if at least one statement is valid
  delay-restart        Don't restart processes
  force                Force addition of package (ignore warnings)
  member               Install package on member (0..9)
  no-copy              Don't save copies of package files
  no-validate          Don't check compatibility with current configuration
  re0                  Install package on RE0
  re1                  Install package on RE1
  reboot               Reboot system after adding package
  unlink               Remove the package after successful installation
  upgrade-with-config-format  
  validate             Check compatibility with current configuration
  validate-on-host     Remote host or user@host for configuration validation
  validate-on-routing-engine  Routing engine for configuration validation
  virtual-machine-package  Add virtual-machine package
  |                    Pipe through a command

Junos 18.2:

{master:0}
user@switch> show version 
localre:
--------------------------------------------------------------------------
Hostname: switch
Model: qfx5200-32c-32q
Junos: 18.1R3.3
JUNOS OS Kernel 64-bit  [20180816.8630ec5_builder_stable_11]
JUNOS OS libs [20180816.8630ec5_builder_stable_11]
JUNOS OS runtime [20180816.8630ec5_builder_stable_11]
JUNOS OS time zone information [20180816.8630ec5_builder_stable_11]
JUNOS OS libs compat32 [20180816.8630ec5_builder_stable_11]
JUNOS OS 32-bit compatibility [20180816.8630ec5_builder_stable_11]
JUNOS py extensions [20180830.023824_builder_junos_181_r3]
JUNOS py base [20180830.023824_builder_junos_181_r3]
JUNOS OS vmguest [20180816.8630ec5_builder_stable_11]
JUNOS OS crypto [20180816.8630ec5_builder_stable_11]
JUNOS network stack and utilities [20180830.023824_builder_junos_181_r3]
JUNOS libs [20180830.023824_builder_junos_181_r3]
JUNOS libs compat32 [20180830.023824_builder_junos_181_r3]
JUNOS runtime [20180830.023824_builder_junos_181_r3]
JUNOS qfx runtime [20180830.023824_builder_junos_181_r3]
JUNOS common platform support [20180830.023824_builder_junos_181_r3]
JUNOS qfx platform support [20180830.023824_builder_junos_181_r3]
JUNOS dcp network modules [20180830.023824_builder_junos_181_r3]
JUNOS modules [20180830.023824_builder_junos_181_r3]
JUNOS qfx modules [20180830.023824_builder_junos_181_r3]
JUNOS qfx Data Plane Crypto Support [20180830.023824_builder_junos_181_r3]
JUNOS daemons [20180830.023824_builder_junos_181_r3]
JUNOS qfx daemons [20180830.023824_builder_junos_181_r3]
JUNOS Services URL Filter package [20180830.023824_builder_junos_181_r3]
JUNOS Services TLB Service PIC package [20180830.023824_builder_junos_181_r3]
JUNOS Services Telemetry [20180830.023824_builder_junos_181_r3]
JUNOS Services SSL [20180830.023824_builder_junos_181_r3]
JUNOS Services SOFTWIRE [20180830.023824_builder_junos_181_r3]
JUNOS Services Stateful Firewall [20180830.023824_builder_junos_181_r3]
JUNOS Services RPM [20180830.023824_builder_junos_181_r3]
JUNOS Services PCEF package [20180830.023824_builder_junos_181_r3]
JUNOS Services NAT [20180830.023824_builder_junos_181_r3]
JUNOS Services Mobile Subscriber Service Container package [20180830.023824_builder_junos_181_r3]
JUNOS Services MobileNext Software package [20180830.023824_builder_junos_181_r3]
JUNOS Services Logging Report Framework package [20180830.023824_builder_junos_181_r3]
JUNOS Services LL-PDF Container package [20180830.023824_builder_junos_181_r3]
JUNOS Services Jflow Container package [20180830.023824_builder_junos_181_r3]
JUNOS Services Deep Packet Inspection package [20180830.023824_builder_junos_181_r3]
JUNOS Services IPSec [20180830.023824_builder_junos_181_r3]
JUNOS Services IDS [20180830.023824_builder_junos_181_r3]
JUNOS IDP Services [20180830.023824_builder_junos_181_r3]
JUNOS Services HTTP Content Management package [20180830.023824_builder_junos_181_r3]
JUNOS Services Crypto [20180830.023824_builder_junos_181_r3]
JUNOS Services Captive Portal and Content Delivery Container package [20180830.023824_builder_junos_181_r3]
JUNOS Services COS [20180830.023824_builder_junos_181_r3]
JUNOS AppId Services [20180830.023824_builder_junos_181_r3]
JUNOS Services Application Level Gateways [20180830.023824_builder_junos_181_r3]
JUNOS Services AACL Container package [20180830.023824_builder_junos_181_r3]
JUNOS SDN Software Suite [20180830.023824_builder_junos_181_r3]
JUNOS Extension Toolkit [20180830.023824_builder_junos_181_r3]
JUNOS Packet Forwarding Engine Support (DC-PFE) [20180830.023824_builder_junos_181_r3]
JUNOS Packet Forwarding Engine Support (M/T Common) [20180830.023824_builder_junos_181_r3]
JUNOS jfirmware [20180830.023824_builder_junos_181_r3]
JUNOS Online Documentation [20180830.023824_builder_junos_181_r3]
JUNOS jail runtime [20180816.8630ec5_builder_stable_11]
JUNOS FIPS mode utilities [20180830.023824_builder_junos_181_r3]
JUNOS Host Software [3.14.52-rt50-WR7.0.0.9_ovp:3.0.9]
JUNOS Host qfx-5e host-control package [18.1R3.3]
JUNOS Host qfx-5e host-platform package [18.1R3.3]
JUNOS Host qfx-5e control-plane package [18.1R3.3]
JUNOS Host qfx-5e platform package [18.1R3.3]
JUNOS Host qfx-5e base package [18.1R3.3]
JUNOS Host qfx-5e data-plane package [18.1R3.3]
 
{master:0}
user@switch> request system software add /var/tmp/jinstall-host-qfx-5e-flex-x86-64-18.2X75-D435.20-secure-signed.tgz ?
Possible completions:
  <[Enter]>            Execute this command
  best-effort-load     Load succeeds if at least one statement is valid
  delay-restart        Don't restart processes
  force                Force addition of package (ignore warnings)
  force-host           Force addition of host os package (ignore version check)  <-- "force-host" option introduced in 18.x for QFX5200
  member               Install package on member (0..9)
  no-copy              Don't save copies of package files
  no-validate          Don't check compatibility with current configuration
  re0                  Install package on RE0
  re1                  Install package on RE1
  reboot               Reboot system after adding package
  unlink               Remove the package after successful installation
  virtual-machine-package  Add virtual-machine package
  |                    Pipe through a command

The "force-host" option on QFX5200s in newer Junos versions for QFX5200 platforms like QFX5200, QFX5220, QFX5120 is introduced to ensure the Host OS Linux as well as the Host Applications get upgraded along with Junos.

Without using the "force-host" option for QFX5200, as seen from 'show version' , the Host OS matches the Junos version.  However, the Linux (WRL) sub version does NOT match.

There two things here; Host Application daemon and WRL components.  This is the reason why we see in 'show version' that the host version updated to the same version as Junos even when upgrading without using the "force-host" option.  This in turn is because the application package is installed and updated.  However, this does not ensure the Linux (WRL) or host scripts get upgraded. The install logs seen on the console (or from Host OS), shows the application package gets upgraded if the existing Linux (WRL) version is compatible with the applications.  In such cases, the WRL will not get upgraded unless "force-host" option is used. Hence, it is always recommended to use "force-host" in QFX5K platforms where this option was not available for QFX5200.

Example upgrade without using "force-host":

user@switch> show version 
localre:
--------------------------------------------------------------------------
Hostname: switch
Model: qfx5200-32c-32q
Junos: 18.1R3.3
JUNOS OS Kernel 64-bit  [20180816.8630ec5_builder_stable_11]
JUNOS OS libs [20180816.8630ec5_builder_stable_11]
JUNOS OS runtime [20180816.8630ec5_builder_stable_11]
JUNOS OS time zone information [20180816.8630ec5_builder_stable_11]
JUNOS OS libs compat32 [20180816.8630ec5_builder_stable_11]
JUNOS OS 32-bit compatibility [20180816.8630ec5_builder_stable_11]
JUNOS py extensions [20180830.023824_builder_junos_181_r3]
JUNOS py base [20180830.023824_builder_junos_181_r3]
JUNOS OS vmguest [20180816.8630ec5_builder_stable_11]
JUNOS OS crypto [20180816.8630ec5_builder_stable_11]
JUNOS network stack and utilities [20180830.023824_builder_junos_181_r3]
JUNOS libs [20180830.023824_builder_junos_181_r3]
JUNOS libs compat32 [20180830.023824_builder_junos_181_r3]
JUNOS runtime [20180830.023824_builder_junos_181_r3]
JUNOS qfx runtime [20180830.023824_builder_junos_181_r3]
JUNOS common platform support [20180830.023824_builder_junos_181_r3]
JUNOS qfx platform support [20180830.023824_builder_junos_181_r3]
JUNOS dcp network modules [20180830.023824_builder_junos_181_r3]
JUNOS modules [20180830.023824_builder_junos_181_r3]
JUNOS qfx modules [20180830.023824_builder_junos_181_r3]
JUNOS qfx Data Plane Crypto Support [20180830.023824_builder_junos_181_r3]
JUNOS daemons [20180830.023824_builder_junos_181_r3]
JUNOS qfx daemons [20180830.023824_builder_junos_181_r3]
JUNOS Services URL Filter package [20180830.023824_builder_junos_181_r3]
JUNOS Services TLB Service PIC package [20180830.023824_builder_junos_181_r3]
JUNOS Services Telemetry [20180830.023824_builder_junos_181_r3]
JUNOS Services SSL [20180830.023824_builder_junos_181_r3]
JUNOS Services SOFTWIRE [20180830.023824_builder_junos_181_r3]
JUNOS Services Stateful Firewall [20180830.023824_builder_junos_181_r3]
JUNOS Services RPM [20180830.023824_builder_junos_181_r3]
JUNOS Services PCEF package [20180830.023824_builder_junos_181_r3]
JUNOS Services NAT [20180830.023824_builder_junos_181_r3]
JUNOS Services Mobile Subscriber Service Container package [20180830.023824_builder_junos_181_r3]
JUNOS Services MobileNext Software package [20180830.023824_builder_junos_181_r3]
JUNOS Services Logging Report Framework package [20180830.023824_builder_junos_181_r3]
JUNOS Services LL-PDF Container package [20180830.023824_builder_junos_181_r3]
JUNOS Services Jflow Container package [20180830.023824_builder_junos_181_r3]
JUNOS Services Deep Packet Inspection package [20180830.023824_builder_junos_181_r3]
JUNOS Services IPSec [20180830.023824_builder_junos_181_r3]
JUNOS Services IDS [20180830.023824_builder_junos_181_r3]
JUNOS IDP Services [20180830.023824_builder_junos_181_r3]
JUNOS Services HTTP Content Management package [20180830.023824_builder_junos_181_r3]
JUNOS Services Crypto [20180830.023824_builder_junos_181_r3]
JUNOS Services Captive Portal and Content Delivery Container package [20180830.023824_builder_junos_181_r3]
JUNOS Services COS [20180830.023824_builder_junos_181_r3]
JUNOS AppId Services [20180830.023824_builder_junos_181_r3]
JUNOS Services Application Level Gateways [20180830.023824_builder_junos_181_r3]
JUNOS Services AACL Container package [20180830.023824_builder_junos_181_r3]
JUNOS SDN Software Suite [20180830.023824_builder_junos_181_r3]
JUNOS Extension Toolkit [20180830.023824_builder_junos_181_r3]
JUNOS Packet Forwarding Engine Support (DC-PFE) [20180830.023824_builder_junos_181_r3]
JUNOS Packet Forwarding Engine Support (M/T Common) [20180830.023824_builder_junos_181_r3]
JUNOS jfirmware [20180830.023824_builder_junos_181_r3]
JUNOS Online Documentation [20180830.023824_builder_junos_181_r3]
JUNOS jail runtime [20180816.8630ec5_builder_stable_11]
JUNOS FIPS mode utilities [20180830.023824_builder_junos_181_r3]
JUNOS Host Software [3.14.52-rt50-WR7.0.0.9_ovp:3.0.9]  <-- current WRL version
JUNOS Host qfx-5e host-control package [18.1R3.3]
JUNOS Host qfx-5e host-platform package [18.1R3.3]rw
JUNOS Host qfx-5e control-plane package [18.1R3.3]
JUNOS Host qfx-5e platform package [18.1R3.3]
JUNOS Host qfx-5e base package [18.1R3.3]
JUNOS Host qfx-5e data-plane package [18.1R3.3]

user@switch> request system software add /var/tmp/jinstall-host-qfx-5e-x86-64-19.4R1.10-secure-signed.tgz reboot 
Verified jinstall-host-qfx-5e-x86-64-19.4R1.10-secure-signed signed by PackageProductionEc_2019 method ECDSA256+SHA256
Pushing Junos image package to the host...
Installing /var/tmp/install-media-qfx-5e-junos-19.4R1.10-secure.tgz
Extracting the package ...

============================================
Current Host kernel version : 3.14.52-rt50-WR7.0.0.9_ovp
Package Host kernel version : 3.14.52-rt50-WR7.0.0.9_ovp
Current Host version        : 3.0.9   
Package Host version        : 3.1.0  
Min host version required for applications: 3.0.7   <-- applications supported with current WRL version
Skipping Host OS upgrade!                           <-- Host OS upgrade skipped
============================================

Setting up Junos host applications for installation ...

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

NOTICE: 'pending' set will be activated at next reboot...
Rebooting. Please wait ...
shutdown: [pid 13446]
Shutdown NOW!

Post-upgrade:

{master:0}
user@switch> show version 
localre:
--------------------------------------------------------------------------
Hostname: switch
Model: qfx5200-32c-32q
Junos: 19.4R1.10
JUNOS OS Kernel 64-bit  [20191115.14c2ad5_builder_stable_11]
JUNOS OS libs [20191115.14c2ad5_builder_stable_11]
JUNOS OS runtime [20191115.14c2ad5_builder_stable_11]
JUNOS OS time zone information [20191115.14c2ad5_builder_stable_11]
JUNOS OS libs compat32 [20191115.14c2ad5_builder_stable_11]
JUNOS OS 32-bit compatibility [20191115.14c2ad5_builder_stable_11]
JUNOS py extensions2 [20191219.030908_builder_junos_194_r1]
JUNOS py extensions [20191219.030908_builder_junos_194_r1]
JUNOS py base2 [20191219.030908_builder_junos_194_r1]
JUNOS py base [20191219.030908_builder_junos_194_r1]
JUNOS OS vmguest [20191115.14c2ad5_builder_stable_11]
JUNOS OS crypto [20191115.14c2ad5_builder_stable_11]
JUNOS network stack and utilities [20191219.030908_builder_junos_194_r1]
JUNOS libs [20191219.030908_builder_junos_194_r1]
JUNOS libs compat32 [20191219.030908_builder_junos_194_r1]
JUNOS runtime [20191219.030908_builder_junos_194_r1]
JUNOS na telemetry [19.4R1.10]
JUNOS Web Management Platform Package [20191219.030908_builder_junos_194_r1]
JUNOS qfx runtime [20191219.030908_builder_junos_194_r1]
JUNOS common platform support [20191219.030908_builder_junos_194_r1]
JUNOS qfx platform support [20191219.030908_builder_junos_194_r1]
JUNOS Openconfig [19.4R1.10]
JUNOS dcp network modules [20191219.030908_builder_junos_194_r1]
JUNOS modules [20191219.030908_builder_junos_194_r1]
JUNOS qfx modules [20191219.030908_builder_junos_194_r1]
JUNOS qfx Data Plane Crypto Support [20191219.030908_builder_junos_194_r1]
JUNOS daemons [20191219.030908_builder_junos_194_r1]
JUNOS qfx daemons [20191219.030908_builder_junos_194_r1]
JUNOS Services URL Filter package [20191219.030908_builder_junos_194_r1]
JUNOS Services TLB Service PIC package [20191219.030908_builder_junos_194_r1]
JUNOS Services Telemetry [20191219.030908_builder_junos_194_r1]
JUNOS Services TCP-LOG [20191219.030908_builder_junos_194_r1]
JUNOS Services SSL [20191219.030908_builder_junos_194_r1]
JUNOS Services SOFTWIRE [20191219.030908_builder_junos_194_r1]
JUNOS Services Stateful Firewall [20191219.030908_builder_junos_194_r1]
JUNOS Services RTCOM [20191219.030908_builder_junos_194_r1]
JUNOS Services RPM [20191219.030908_builder_junos_194_r1]
JUNOS Services PCEF package [20191219.030908_builder_junos_194_r1]
JUNOS Services NAT [20191219.030908_builder_junos_194_r1]
JUNOS Services Mobile Subscriber Service Container package [20191219.030908_builder_junos_194_r1]
JUNOS Services MobileNext Software package [20191219.030908_builder_junos_194_r1]
JUNOS Services Logging Report Framework package [20191219.030908_builder_junos_194_r1]
JUNOS Services LL-PDF Container package [20191219.030908_builder_junos_194_r1]
JUNOS Services Jflow Container package [20191219.030908_builder_junos_194_r1]
JUNOS Services Deep Packet Inspection package [20191219.030908_builder_junos_194_r1]
JUNOS Services IPSec [20191219.030908_builder_junos_194_r1]
JUNOS Services IDS [20191219.030908_builder_junos_194_r1]
JUNOS IDP Services [20191219.030908_builder_junos_194_r1]
JUNOS Services HTTP Content Management package [20191219.030908_builder_junos_194_r1]
JUNOS Services Crypto [20191219.030908_builder_junos_194_r1]
JUNOS Services Captive Portal and Content Delivery Container package [20191219.030908_builder_junos_194_r1]
JUNOS Services COS [20191219.030908_builder_junos_194_r1]
JUNOS AppId Services [20191219.030908_builder_junos_194_r1]
JUNOS Services Application Level Gateways [20191219.030908_builder_junos_194_r1]
JUNOS Services AACL Container package [20191219.030908_builder_junos_194_r1]
JUNOS SDN Software Suite [20191219.030908_builder_junos_194_r1]
JUNOS Extension Toolkit [20191219.030908_builder_junos_194_r1]
JUNOS Phone-home [20191219.030908_builder_junos_194_r1]
JUNOS Packet Forwarding Engine Support (DC-PFE) [20191219.030908_builder_junos_194_r1]
JUNOS Packet Forwarding Engine Support (M/T Common) [20191219.030908_builder_junos_194_r1]
JUNOS Juniper Malware Removal Tool (JMRT) [1.0.0+20191219.030908_builder_junos_194_r1]
JUNOS J-Insight [20191219.030908_builder_junos_194_r1]
JUNOS jfirmware [20191219.030908_builder_junos_194_r1]
JUNOS Online Documentation [20191219.030908_builder_junos_194_r1]
JUNOS jail runtime [20191115.14c2ad5_builder_stable_11]
JUNOS FIPS mode utilities [20191219.030908_builder_junos_194_r1]
JUNOS Host Software [3.14.52-rt50-WR7.0.0.9_ovp:3.0.9]  <-- WRL version not upgraded
JUNOS Host qfx-5e host-control package [19.4R1.10]      <-- Application packages got upgraded
JUNOS Host qfx-5e host-platform package [19.4R1.10]     <-- Application packages got upgraded
JUNOS Host qfx-5e control-plane package [19.4R1.10] 
JUNOS Host qfx-5e platform package [19.4R1.10]
JUNOS Host qfx-5e base package [19.4R1.10] 
JUNOS Host qfx-5e data-plane package [19.4R1.10] 

Sample upgrade using "force-host":

{master:0}
user@switch> show version | no-more
localre:
--------------------------------------------------------------------------
Hostname: switch
Model: qfx5200-32c-32q
Junos: 18.2X75-D435.20
JUNOS OS Kernel 64-bit  [20200423.d6acdc5_builder_stable_11]
JUNOS OS libs [20200423.d6acdc5_builder_stable_11]
JUNOS OS runtime [20200423.d6acdc5_builder_stable_11]
JUNOS OS time zone information [20200423.d6acdc5_builder_stable_11]
JUNOS OS libs compat32 [20200423.d6acdc5_builder_stable_11]
JUNOS OS 32-bit compatibility [20200423.d6acdc5_builder_stable_11]
JUNOS py extensions [20210215.051819_builder_junos_182_x75_d435]
JUNOS py base [20210215.051819_builder_junos_182_x75_d435]
JUNOS OS vmguest [20200423.d6acdc5_builder_stable_11]
JUNOS OS crypto [20200423.d6acdc5_builder_stable_11]
JUNOS network stack and utilities [20210215.051819_builder_junos_182_x75_d435]
JUNOS libs [20210215.051819_builder_junos_182_x75_d435]
JUNOS libs compat32 [20210215.051819_builder_junos_182_x75_d435]
JUNOS runtime [20210215.051819_builder_junos_182_x75_d435]
JUNOS na telemetry [18.2X75-D435.20]
JUNOS Web Management Platform Package [20210215.051819_builder_junos_182_x75_d435]
JUNOS qfx runtime [20210215.051819_builder_junos_182_x75_d435]
JUNOS common platform support [20210215.051819_builder_junos_182_x75_d435]
JUNOS qfx platform support [20210215.051819_builder_junos_182_x75_d435]
JUNOS Openconfig [18.2X75-D435.20]
JUNOS dcp network modules [20210215.051819_builder_junos_182_x75_d435]
JUNOS modules [20210215.051819_builder_junos_182_x75_d435]
JUNOS qfx modules [20210215.051819_builder_junos_182_x75_d435]
JUNOS qfx Data Plane Crypto Support [20210215.051819_builder_junos_182_x75_d435]
JUNOS daemons [20210215.051819_builder_junos_182_x75_d435]
JUNOS qfx daemons [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services URL Filter package [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services TLB Service PIC package [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services Telemetry [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services SSL [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services SOFTWIRE [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services Stateful Firewall [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services RPM [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services PCEF package [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services NAT [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services Mobile Subscriber Service Container package [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services MobileNext Software package [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services Logging Report Framework package [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services LL-PDF Container package [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services Jflow Container package [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services Deep Packet Inspection package [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services IPSec [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services IDS [20210215.051819_builder_junos_182_x75_d435]
JUNOS IDP Services [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services HTTP Content Management package [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services Flowd MS-MPC Software package [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services Crypto [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services Captive Portal and Content Delivery Container package [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services COS [20210215.051819_builder_junos_182_x75_d435]
JUNOS AppId Services [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services Application Level Gateways [20210215.051819_builder_junos_182_x75_d435]
JUNOS Services AACL Container package [20210215.051819_builder_junos_182_x75_d435]
JUNOS SDN Software Suite [20210215.051819_builder_junos_182_x75_d435]
JUNOS Extension Toolkit [20210215.051819_builder_junos_182_x75_d435]
JUNOS Packet Forwarding Engine Support (DC-PFE) [20210215.051819_builder_junos_182_x75_d435]
JUNOS Packet Forwarding Engine Support (M/T Common) [20210215.051819_builder_junos_182_x75_d435]
JUNOS J-Insight [20210215.051819_builder_junos_182_x75_d435]
JUNOS jfirmware [20210215.051819_builder_junos_182_x75_d435]
JUNOS Online Documentation [20210215.051819_builder_junos_182_x75_d435]
JUNOS jail runtime [20200423.d6acdc5_builder_stable_11]
JUNOS FIPS mode utilities [20210215.051819_builder_junos_182_x75_d435]
JUNOS Host Software [3.14.52-rt50-WR7.0.0.9_ovp:3.1.0]   <-- current WRL version
JUNOS Host qfx-5e host-control package [18.2X75-D435.20]
JUNOS Host qfx-5e host-platform package [18.2X75-D435.20]
JUNOS Host qfx-5e control-plane package [18.2X75-D435.20]
JUNOS Host qfx-5e platform package [18.2X75-D435.20]
JUNOS Host qfx-5e base package [18.2X75-D435.20]
JUNOS Host qfx-5e data-plane package [18.2X75-D435.20]

{master:0}
user@switch> ...tall-host-qfx-5e-flex-x86-64-18.2X75-D435.20-secure-signed.tgz force-host                                        
Apr 27 18:25:35
Verified jinstall-host-qfx-5e-flex-x86-64-18.2X75-D435.20-secure-signed signed by PackageProductionECP256_2021 method ECDSA256+SHA256
Pushing Junos image package to the host...
Installing /var/tmp/install-media-qfx-5e-junos-18.2X75-D435.20-secure.tgz
Extracting the package ...

============================================
Host OS upgrade is FORCED  <-- Host OS upgrade staged due to "force-host"
Current Host kernel version : 3.14.52-rt50-WR7.0.0.9_ovp
Package Host kernel version : 3.14.52-rt50-WR7.0.0.9_ovp
Current Host version        : 3.1.0 
Package Host version        : 3.0.9 
Min host version required for applications: 3.0.7
============================================

Validate linux image...
Setting up Junos host applications for installation ...
Current junos instance is 0
Installing Host OS ...
upgrade_platform: -------------------
upgrade_platform: Parameters passed:
upgrade_platform: silent=0
upgrade_platform: package=/var/tmp/jinstall-qfx-5e-junos-18.2X75-D435.20-secure-linux.tgz
upgrade_platform: clean install=0
upgrade_platform: on primary   =0
upgrade_platform: clean upgrade=0
upgrade_platform: Need reboot after staging=0
upgrade_platform: -------------------
upgrade_platform:
upgrade_platform: Checking input /var/tmp/jinstall-qfx-5e-junos-18.2X75-D435.20-secure-linux.tgz ...
upgrade_platform: Input package /var/tmp/jinstall-qfx-5e-junos-18.2X75-D435.20-secure-linux.tgz is valid.
Error: efivarfs is not supported
secure boot status is unknown
upgrade_platform: Staging the upgrade package - /var/tmp/jinstall-qfx-5e-junos-18.2X75-D435.20-secure-linux.tgz..
./
./upgrade_platform
./platform_info
./host-version
./version.txt
./initrd.cpio.gz
./bzImage-intel-x86-64.bin
./initramfs.cpio.gz
./linux.checksum
./grub/
./grub/grub.conf
./grub/grub.efi
./initramfs.cpio.gz.psig
./bzImage-intel-x86-64.bin.psig
bzImage-intel-x86-64.bin: OK
initramfs.cpio.gz: OK
version.txt: OK
upgrade_platform: Checksum verified and OK...
upgrade_platform: Staging of /var/tmp/jinstall-qfx-5e-junos-18.2X75-D435.20-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!

{master:0}
user@switch> request system reboot at now
Reboot the system at now? [yes,no] (no) yes 

*** FINAL System shutdown message from user@switch ***    

System going down IMMEDIATELY                                                  

Shutdown NOW!
[pid 41385]

Post-upgrade:

{master:0}
user@switch> show version
localre:
--------------------------------------------------------------------------
Hostname: switch
Model: qfx5200-32c-32q
Junos: 18.2X75-D435.20 flex
JUNOS OS Kernel 64-bit FLEX [20200423.d6acdc5_builder_stable_11]
JUNOS OS libs [20200423.d6acdc5_builder_stable_11]
JUNOS OS runtime [20200423.d6acdc5_builder_stable_11]
JUNOS OS time zone information [20200423.d6acdc5_builder_stable_11]
JUNOS OS libs compat32 [20200423.d6acdc5_builder_stable_11]
JUNOS OS 32-bit compatibility [20200423.d6acdc5_builder_stable_11]
JUNOS py extensions [20210215.051819_builder_junos_182_x75_d435]
JUNOS py base [20210215.051819_builder_junos_182_x75_d435]
JUNOS OS vmguest [20200423.d6acdc5_builder_stable_11]
JUNOS OS crypto [20200423.d6acdc5_builder_stable_11]
JUNOS network stack and utilities [20210215.051819_builder_junos_182_x75_d435]
JUNOS libs [20210215.051819_builder_junos_182_x75_d435]
JUNOS libs compat32 [20210215.051819_builder_junos_182_x75_d435]
JUNOS runtime [20210215.051819_builder_junos_182_x75_d435]
JUNOS na telemetry [18.2X75-D435.20]
JUNOS Web Management Platform Package [20210215.051819_builder_junos_182_x75_d435]
JUNOS qfx runtime [20210215.051819_builder_junos_182_x75_d435]
JUNOS common platform support [20210215.051819_builder_junos_182_x75_d435]
JUNOS qfx platform support [20210215.051819_builder_junos_182_x75_d435]
JUNOS Openconfig [18.2X75-D435.20]
JUNOS dcp network modules [20210215.051819_builder_junos_182_x75_d435]
JUNOS modules [20210215.051819_builder_junos_182_x75_d435]
JUNOS qfx modules [20210215.051819_builder_junos_182_x75_d435]
JUNOS qfx Data Plane Crypto Support [20210215.051819_builder_junos_182_x75_d435]
JUNOS daemons [20210215.051819_builder_junos_182_x75_d435]
JUNOS qfx daemons [20210215.051819_builder_junos_182_x75_d435]
JUNOS SDN Software Suite [20210215.051819_builder_junos_182_x75_d435]
JUNOS Extension Toolkit [20210215.051819_builder_junos_182_x75_d435]
JET app jpuppet [3.6.1_4.0]
JUNOS Packet Forwarding Engine Support (DC-PFE) [20210215.051819_builder_junos_182_x75_d435]
JUNOS Packet Forwarding Engine Support (M/T Common) [20210215.051819_builder_junos_182_x75_d435]
JUNOS J-Insight [20210215.051819_builder_junos_182_x75_d435]
JUNOS jfirmware [20210215.051819_builder_junos_182_x75_d435]
JUNOS Online Documentation [20210215.051819_builder_junos_182_x75_d435]
JUNOS jail runtime [20200423.d6acdc5_builder_stable_11]
JUNOS FIPS mode utilities [20210215.051819_builder_junos_182_x75_d435]
JET app chef [11.10.4_3.0]
JUNOS Host Software [3.14.52-rt50-WR7.0.0.9_ovp:3.0.9]  <-- WRL also upgraded
JUNOS Host qfx-5e host-control package [18.2X75-D435.20] <-- Application packages got upgraded
JUNOS Host qfx-5e host-platform package [18.2X75-D435.20] <-- Application packages got upgraded
JUNOS Host qfx-5e control-plane flex package [18.2X75-D435.20]
JUNOS Host qfx-5e platform package [18.2X75-D435.20]
JUNOS Host qfx-5e base package [18.2X75-D435.20]
JUNOS Host qfx-5e data-plane package [18.2X75-D435.20]
Junos for Automation Enhancement

Edited platforms

• Upgrading Software