The old beta version of VRoid Studio and the support for it have been discontinued.
*Only v0.14.0 is still available.
VRoid Studio Download Link
https://vroid.com/studio/releases
The models you have created on the old beta versions cannot be used as they are on the stable version, as they would need updating.
You will need to convert your models via the Conversion feature.
For more detail on how to convert your models' data, check this article.
How to use models from the old beta version
If you wish to edit a model you created on a old beta version, please download VRoid Studio ver. 0.14.0.