Hi Karthi,
For your queries:
1) Yes, if you are upgrading to latest version in both Production and Sub-Production environment, then you will have to use new license on both locations.
2) Well, if you are using Aspose.Cells for Java on different operating systems and different versions of Java, then same license will work, however, if you want to use Aspose.Cells for .NET and Java, then you need separate licenses for .NET and Java platforms.
3) No need to report in the PS forum.
4) For your information, licenses should work with any release (of the product) which was published in last one year.
5) No, please check 4.
6) It depends on the license type, check this:
Hope, this helps a bit.
Thank you.