As we explained in our last release, we are sunsetting the Terrain Editor tool in Sansar in the interests of optimizing performance. We encourage you to instead use your preferred terrain creator and import your terrain as an object into Sansar.
Any terrain created by the Sansar Terrain Editor tool and using terrain heightmaps will be replaced with a default placeholder at the end of April release. So if you are a Creator who has used the Sansar Terrain Editor tool, please be prepared for this change.
In other words, if you're a Sansar content creator who's created a landscape with the terrain editor, you have a few weeks to replace it with a landscape built with an offline editor, or it'll be replaced by the company. Which strikes me as a pretty drastic way of optimizing content that may cause confusion.