Can I show 2 Releases as one Gantt line (union or combined or stacked)?

Hi @Sujith,
You need to create an aggregate in Fix version dimension:

Aggregate({
  [Fix Version].[Demo].[Unreleased].[1.0],
  [Fix Version].[Demo].[Unreleased].[2.0]
  })

Here you can see an example of how to do it: