Hi Sachin,
You can, and you're not violating any license doing so. However, keep in mind that those features might be removed from the CE codebase in the future, as they were clearly documented as PE features. This will, if you use those features in the CE, make upgrading significantly harder.
So, if you're planning to use Orbeon Forms long term, and you need those features, I'd encourage you to use the PE, as it will make upgrading easier, and doing so you're supporting the development of Orbeon Forms ;).
Alex
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