Hello @Musngi,Meg,PH-Manila , Thanks for using Microsoft Q&A Platform.
To change the API version, select 'Project Settings' and then choose the API version of your choice and then click 'Save' in the document intelligence studio.
As, Custom classification models are supported by v4.0: 2024-02-29-preview, 2024-07-31-preview and v3.1: 2023-07-31 (GA) APIs. Downgrading from latest preview to 024-07-31-preview may not be an issue.
However, please always check the migration guide. Here is the documentation you can refer to: https://learn.microsoft.com/en-us/azure/ai-services/document-intelligence/changelog-release-history?view=doc-intel-4.0.0&tabs=csharp
I hope this helps.
Regards,
Vasavi
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