Since upgraded to rails 4.2, I see digest value in asset tags (stylesheet and javascripts etc.)
Example:
rails 4.2
<link rel="stylesheet" media="all" href="/assets/application-53ef528cfe7c9195cd752901d8eb6f667dc45cdcadb23287443dcc2b8cba459a.css">
before rails 4.2
<link rel="stylesheet" media="all" href="/assets/application.css">
Is that expected?