There’s plenty of info on the net about how to install and make work the old, unsupported Cisco VPN Client on Windwos 10, so I’ll avoid making cut/paste here.
The only advice I would like to add is that contrary to what I read around, it was perfectly feasible to me to use directly the Cytrix DNEupdate package rather that having to install the whole SonicWALL VPN client just for the sake to have Cytrix DNE.
On a test machine I tried the much advised method with SonicWALL VPN client, and it worked, but when I removed it to retain only the DNE, it left my test system heavily cluttered with garbage.
Among the others, it left an Inf file for its SWVNIC virtual NIC driver, the driver files in the drivers repository; several registry entries; a firewall policy and a shell extension to create a new VPN profile (but are these for, if I remove the whole program)? Completely inacceptable for me so in my personal opinion, this VPN client should be avoided at least if not interested in itself. If nonetheless you want to try it, I advise to check to have a recent restore point, to avoid a tedious search/delete through the registry and the file system.
So I used the dneupdate64.msi which can be found here . At the time of writing, the package is 1.867.776 bytes long and contains version 4.35.18936 of Dnei64x.dll in. Moreover if I inspecti the content of the Sonicwall VPN client installer, GVCSetup64_4.9.9.1016_EN.exe, I find the same version of the file.