Recently, we had an interesting lunch-break with the rails 3.1. asset-pipeline in production mode. Daniel Zahn made a blogpost about our journey, precompiling assets, fingerprinting, Haml, Sass & Compass and what he calls "the dark heinous hutch".
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