• that we treat it as a separate question, and avoid duplicating the instructions in How to prevent updating of a specific package?. A specific example of how to pin just the Skype packages might be OK, but let's not make this question more general than it needs to be, if we're reopening it based on its notable specificity.

• that we answer it quickly, so answers don't accumulate in it that ought to be in How to prevent updating of a specific package? instead.

You want to keep a particular version of the package skype for the foreseeable future, even when newer versions are available, and even if you install Ubuntu again from scratch.

First, assuming this beta version is packaged the same way as the current version, there are actually two packages--skype, and skype-bin.

There are two things you must do, for each of these packages:

1. Pin them at their current versions so they're left alone when you update software. That's been covered in this question:

   • How to prevent updating of a specific package?

2. Keep copies of the .deb package files used to install them. You'll probably find them in /var/cache/apt/archives. Their names should begin with skype_2.2.0.35- and skype-bin_2.2.0.35- (and both end in .deb).

   Back them up, and if you have to reinstall Ubuntu from scratch or if you want to install this version of Skype on another machine, just install those packages. One way to install them is to run this command, after cding to the folder that contains the .deb files:

    sudo dpkg -i skype_2.2.0.35-*.deb skype-bin_2.2.0.35-*.deb
   

   If you're told one or both of these packages can't be completely configured because you don't have the necessary dependencies installed, make sure you're connected to the Internet and run these commands:

    sudo apt-get -f install
    sudo dpkg --configure -a
   

Finally, please note that if you continue to use an old version of Skype that is no longer supported upstream:

• It may stop working, or stop working properly, over time.
• It may contain security vulnerabilities fixed in later versions.

I've included this sample answer to demonstrate that this question really can be answered in a way that treats it as a separate, non-duplicate question. This meta answer should not become the answer to that main question. If we reopen this question and an answer is posted, I plan to edit it out of this meta answer.

• that we treat it as a separate question, and avoid duplicating the instructions in How to prevent updating of a specific package?. A specific example of how to pin just the Skype packages might be OK, but let's not make this question more general than it needs to be, if we're reopening it based on its notable specificity.

• that we answer it quickly, so answers don't accumulate in it that ought to be in How to prevent updating of a specific package? instead.

You want to keep a particular version of the package skype for the foreseeable future, even when newer versions are available, and even if you install Ubuntu again from scratch.

First, assuming this beta version is packaged the same way as the current version, there are actually two packages--skype, and skype-bin.

There are two things you must do, for each of these packages:

1. Pin them at their current versions so they're left alone when you update software. That's been covered in this question:

   • How to prevent updating of a specific package?

2. Keep copies of the .deb package files used to install them. You'll probably find them in /var/cache/apt/archives. Their names should begin with skype_2.2.0.35- and skype-bin_2.2.0.35- (and both end in .deb).

   Back them up, and if you have to reinstall Ubuntu from scratch or if you want to install this version of Skype on another machine, just install those packages. One way to install them is to run this command, after cding to the folder that contains the .deb files:

    sudo dpkg -i skype_2.2.0.35-*.deb skype-bin_2.2.0.35-*.deb
   

   If you're told one or both of these packages can't be completely configured because you don't have the necessary dependencies installed, make sure you're connected to the Internet and run these commands:

    sudo apt-get -f install
    sudo dpkg --configure -a
   

Finally, please note that if you continue to use an old version of Skype that is no longer supported upstream:

• It may stop working, or stop working properly, over time.
• It may contain security vulnerabilities fixed in later versions.

I've included this sample answer to demonstrate that this question really can be answered in a way that treats it as a separate, non-duplicate question. This meta answer should not become the answer to that main question. If we reopen this question and an answer is posted, I plan to edit it out of this meta answer.

Update: I've changed the question's title to How to prevent Skype from upgrading and keep the old version for reinstallation? (from How to save an old package?) so that it's clearer what the OP is asking (and what I believe we can answer as a separate, non-duplicate question).