There is no reason to think that the method described in that thread will not work on the latest versions of Ubuntu. When some users had experienced problems, they were asked what version they were running in case there was a problem with newer versions, but no such problem was shown to be occurring.
I recommend that you read the entire forum thread (it's five pages, which is longer than some threads but shorter than many) and try the technique as described. It should work. Before using it "in production," you should of course test it with a program where there are no negative consequences associated with it accessing the Internet, in case either the method doesn't work or you have made a mistake.
As an alternative technique, you can create a virtual machine (for example, with VirtualBox) without Internet access (you could even make it have zero virtual network adapters) and run the program on that virtual machine. This may be preferable for programs whose behavior you don't fully trust, because then you have a greater degree of isolation between the program and your (host) Ubuntu system, and also because you can create a snapshot before running the program and revert the VM to that snapshot afterwards.
Of course, if you don't trust a program to behave properly, you should strongly consider not running it at all. When a developer creates a program that disrespects its users' privacy, no matter what the reason is in the mind of the developer, this is an indication that the developer does not respect your privacy and any program the developer has authored (including that one) may disrespect your privacy in other ways. With free open source software, it is possible to vet the code to determine if this is the case (though practically speaking, it may be nontrivial to do so). But for proprietary software, this is not generally an option.