Thank Marco,
We will try the upgrade utility.
BTW. Cesium for unity provides error/warning messages in the editor console when encountering issues in the tileset data (unsupported version, corrupted json etc.)
As we change tilesets in runtime we cannot use thess messages and we need better visibility for such issues through api, exceptions or method return code.
for example: currently there is no indication when setting CesiumGeoreference.url to a wrong address or corrupted json during run time.
Thanks again