Steps to install new VPN client for UBUNTU without upgrading the ADC

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1. Replace the file nsgclient18_64.deb in /var/netscaler/gui/vpn/scripts/linux/ on ADC
2. Replace the file nsepa18.deb in /var/netscaler/gui/epa/scripts/linux/ on ADC
3. Open /var/netscaler/gui/vpn/scripts/linux/clientversions.xml  
4. For EPA plugin, replace the following line (line number 3) with new version.

    <component pkgname="nsepa18" currentversion="1.0.0.x" minversion="1.0.0.x" ostype="ubuntu64" minkernelversion="0" maxkernelversion="100" updatetype="compatible" action="/epa/scripts/linux/nsepa18.deb" />

    to

    <component pkgname="nsepa18" currentversion="1.0.0.46" minversion="1.0.0.46" ostype="ubuntu64" minkernelversion="0" maxkernelversion="100" updatetype="compatible" action="/epa/scripts/linux/nsepa18.deb" />

5. For VPN plugin, replace the following line (line number 8) with new version.

    <component pkgname="nsgclient18" currentversion="1.0.0.x" minversion="1.0.0.x" ostype="ubuntu64" minkernelversion="3.0" maxkernelversion="5.0" updatetype="compatible" action="/vpn/scripts/linux/nsgclient18_64.deb" />

    to 

    <component pkgname="nsgclient18" currentversion="23.5.2" minversion="23.5.2" ostype="ubuntu64" minkernelversion="3.0" maxkernelversion="5.0" updatetype="compatible" action="/vpn/scripts/linux/nsgclient18_64.deb" />

6. Run the commands "rm -rf /netscaler/ns_gui" and "ln -s /var/netscaler/gui /netscaler/ns_gui" on ADC shell prompt.
7. Run the command "set vpn parameter -clientversions all" on ADC command line.
8. Run the command "flush cache contentgroup loginstaticobjects" on ADC command line.
9. The clients should be able to install the new version of Ubuntu VPN/EPA clients.


FIXES :

VERSION - 23.5.2/1.0.0.46
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1. VPN auto-upgrade issue

VERSION - 1.0.0.161/1.0.0.46
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1. Transfer login does not work with Linux VPN plugin
2. EPA enhancement to check for services


VERSION - 1.0.0.157/1.0.0.42
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1. VPN and EPA plugin support for Ubuntu 20.x version. 1.0.0.157(VPN plugin) and 1.0.0.42(EPA plugin) will work for both Ubuntu 18.x and 20.x versions.


VERSION - 1.0.0.146
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1. Ubuntu plugin crashes if files larger than 3GB are transferred through the VPN.
2. Added dependency of package resolvconf on installation.


NOTE : 
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1. On Ubuntu 20.x, if a user downloads the installers from Firefox browser and chooses "Open With", then the installation might fail. This is a known issue on Ubuntu 20 and not a client issue. This is because Firefox downloads the installer in a temporary location and if user chooses "Open With", then Software Installer fails to install from this temporary location.
So, the users will have to select "Save File" which will download the installers in "Downloads" folder. The user can double click the download file and install it via Ubuntu Software or Software Installer.

Bug opened against Ubuntu : https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1908469

2. Also, note that the download button will say "Download for Ubuntu 18" but since the new installer is replaced, it'll work for both Ubuntu 18 as well as 20. The label for that button will be changed in next release of ADC.