TLDR: Browser implementations of HTTP/2 push are horrible. You might end up with worse performance than without pushing. However, the article includes a great explanation of how HTTP/2 push are supposed to integrate with browser APIs.
Rails Long Term Support
Rails LTS provides security patches for old versions of Ruby on Rails (2.3, 3.2, 4.2 and 5.2)
Prevents you from data breaches and liability risks