I disabled automatic updates in Skype portable and never had them enabled yet I keep getting the update notification once when starting the program and a second time after logging in.
As a side note I used to use skype 4.2 and 5.5 portable. The network refused to allow me to sign in using those. I last used the just a few months ago. Anyone know what happened there?
I'm pretty sure that Skype's update check setting is a local registry key that can only be set by an admin.
As to older versions, they're going though and locking older versions out of the network after users have had more than enough time to upgrade. As they should since the older versions have security issues.
Sometimes, the impossible can become possible, if you're awesome!