Need the version number on the last Skype that was fully accessible
It's my understanding that developers are only allowed to make apps available through official channels. This means either the App Store or what are called ad-hoc releases. The latter are generally used for testing of beta builds, and although they can be distributed via email, the process is still tightly controlled by Apple. The developer has to register your iDevice under their developer account, and then create a custom build of the app that can only be used on that iDevice. Not only is this time consuming for the developer, but there are also limits on the number of iDevices that they can register. This makes it very unlikely that they would do this for an old version of their app.
Distributing or sharing apps outside of these official channels would breach Apple's terms and conditions and the copyright of the developer. So, although there are good reasons for people wanting the older version of the Skype app, AppleVis would in no way endorse or support sharing of the relevant file.