How to undo changes/deletion on dataflows?

Hi ZhengTzer ,

Thanks for using Fabric Community.
Yes your understanding is correct. At present you cannot undo changes/deletion on dataflows.

At present DataFlow Gen 2 supports only this funcationality - click here 

How to save and publish your dataflow - Microsoft Fabric | Microsoft Learn

And coming to other query, Versioning in DataFlow Gen2 please check here - link 

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Hope this is helpful. Please do let me know incase of further queries.