Is offline terrain support deprecated?

I am new to Cesium.
I want to try offline terrain feature and followed the steps in
"http://blog.mastermaps.com/2014/10/3d-terrains-with-cesium.html".

But having some problems like,
"An error occured in "CesiumProvider": Failed to obtain terrain tile X:0 Y: 0 Level:0.
.......
"

Lastly, I tried to access "https://cesiumjs.org/data-and-assets/terrain/small-terrain.html",but page is giving 404.

Is there any working sample offline terrain data?

Or this feature is deprecated?

Hello,

Offline terrain is supported, but you will need a terrain dataset hosted locally. Under our terms of use, you may not download our STK World Terrain tileset for offline use.

AGI (the company that employs most of the Cesium team) has a commercial product available for generating terrain called the STK Terrain Server. You can learn more about that here: http://www.agi.com/products/stk/terrain-server/

That blog post also gave several suggestions for creating a terrain tileset.

Best,

Hannah