Depends on your definition of support.
XNA is based on DirectX 9 and that era of SDKs. Those technologies are not changing, consequently there is little need for XNA updates. In that regard XNA is a fixed target.
Microsoft has said it has no plans to update the SDK. This makes sense because it is used primarily for Xbox 360 and that hardware is not changing. Perhaps in nine months or a year they will announce a successor or update to handle XBox One, but that is just wild speculation and rumor.
Many people still actively use XNA because they want to publish their games on the Xbox 360's XBLIG service, or because they want to use the features XNA offers.
There are many active communities of XNA developers.