Description

Before Junos 15.1, you can tell if a version is EEOL (Extended End of Life) by checking https://support.juniper.net/support/eol/software/junos/

If there's a "1" before the release, then it its an EEOL version.
Example:

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1  Extended End of Life (EEOL) Release (pre-15.1 Releases):
EOE date: The date thirty-six (36) months after first general availability date.
EOL/EOS date: The date six (6) months after the EOE date.
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In this example,  Junos OS 14.2 is an EEOL version. However, after 15.1, there's no such tag any longer. Then how we you tell if it's an EEOL version?

Solution

After Junos 15.1, the version whose "End of Engineering" is three years later than "FRS Date" will be considered EEOL.

Example:

18.3 is an EEOL version:
Junos OS 18.3 09/26/2018 09/26/2021
 
20.1 is not an EEOL version :
Junos OS 20.1 03/27/2020 03/27/2022
 
 This method can be used to confirm if a version is a EEOL or not.