This follows the company's decision to base its mobile devices on Windows 10 Mobile, to ensure, in the main, a unified codebase for all hardware.
On its support page, Microsoft says that the Skype app for Windows Phone 8 and 8.1 will continue to work until early 2017 after support ends, but adds cryptically "possibly with some limitations".
By early 2017, the company says it hopes to have moved Skype calling to the cloud.
A similar situation has been outlined for Android: the latest Skype, 6.2 or higher, will run with Android 4.03 or later versions. Android 4.02 and earlier versions will not be supported after October and Skype will only continue to work on these until early 2017.
Microsft also said that Skype was fully supported on ARMv7 processors or those which could run its instruction set. But on devices with ARMv6 processors, video calling is not supported.
The company also says that the latest versions of Skype will only run on OS X 10.9 or higher. For users of OS X 10.6 and earlier versions, the October support deadline and use until early 2017 applies.
No change has been specified for Linux users of the Skype client. A new client was announced on 14 July.