Microsoft have stated they no longer support the Skype Desktop API,
preferring to support mobile and Windows Metro interfaces.
They also say from September the Skype Desktop API will no longer work.
This mean third party applications such as Cortex will no longer be
able to use Skype to make or receive calls or send SMS messages.

Skype will only offer a URI API.
This does not appear to allow the contacts list to be found.
Neither does it allow sending SMS messages.

Not sure it will help but those who use Skype within Cortex might
like to turn off automatic updates in Skype - Options | Advance | Automatic updates
to prevent the downgrade.