This article explains the installation failure of JSU on PTX EVO with the error message "JSU base release is different from current release."

Installation failure messages will be seen as below:

labroot@re> request system software add /var/tmp/junos-evo-install-ptx-x86-64-23.4R2-S3-J8.1-EVO.iso                 
Adding software images. This process can take several minutes. Please be patient...
Download and Validate in Progress
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re0: Running prechecks for JSU image...
re0: Error: JSU base release 23.4R2-S3.11-EVO is different from Current Release: 23.4R2-S3.10-EVO...Exiting
re0: Installation failed
re0: Version 'junos-evo-install-ptx-x86-64-23.4R2-S3-J8.1-EVO' - not found!
ERROR: JSU base release is different from current release. Node:re0 Image: re0:/var/tmp/junos-evo-install-ptx-x86-64-23.4R2-S3-J8.1-EVO.iso
Validation and download failed. Aborting upgrade.

The upgrade process failed due to a mismatch between the JSU's base release and the current release running on the device.

The mentioned JSU junos-evo-install-ptx-x86-64-23.4R2-S3-J8.1-EVO.iso requires the base version 23.4R2-S3.11-EVO.