Is there Java version compatibility table, and can I download old versions of jar file?

Thank you all for great software and active community.

I'm trying to install and use but I faced a problem which someone already faced:

• Unsupported major.minor version 52.0 - do I need java 8?
• (howto) Test your GATK installation

Thanks to them, I made it on my local, but on the other hand I can't change Java version in some environments (shared server for instance).
Then, let me ask 2 questions.

1. Is it possible to download old versions of jar file?
   • https://github.com/broadgsa/gatk/releases shows old versions but archives are not submitted
   • Do I need to build jar file of old versions by myself?
2. Is there any table for compatibility between GATK version and Java version?
   • so that we can understand which version of Java (or GATK) we should prepare