Differences between Supported Kernel and Legacy Kernel

Hi,

I am just wondering what is the differences between Supported Kernel and Legacy Kernel? I am reviewing the possibility to install SEP in the Linux server and my spec as below:-

[root home]# uname -a
Linux 2.6.18-164.el5 #1 SMP Tue Aug 18 15:51:48 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

[root proc]# lsb_release -a
LSB Version: :core-3.1-amd64:core-3.1-ia32:core-3.1-noarch:graphics-3.1-amd64:graphics-3.1-ia32:graphics-3.1-noarch
Distributor ID: RedHatEnterpriseServer
Description: Red Hat Enterprise Linux Server release 5.4 (Tikanga)
Release: 5.4
Codename: Tikanga

[root proc]# rpm -qa 'release'
redhat-release-5Server-5.4.0.3
redhat-release-notes-5Server-29

[root etc]# cat redhat-release
Red Hat Enterprise Linux Server release 5.4 (Tikanga)

[root etc]# java -version
java version "1.6.0_19"
Java(TM) SE Runtime Environment (build 1.6.0_19-b04)
Java HotSpot(TM) Server VM (build 16.2-b04, mixed mode)

It appears in the Legacy kernel for the Symantec Endpoint Protection 12.1.5 client for Linux but supported Operating System is Red Hat Enterprise Linux Server (RHEL) 5U7 - 5U10, 6U2 - 6U5; 32-bit and 64-bit. Please advise.

https://support.symantec.com/en_US/article.TECH224712.html
https://support.symantec.com/en_US/article.TECH223240.html#12.1.5.Legacy

Regards
Kwan