Amo Chohan wrote a rundown of the big changes coming tot PHP 7.1

  • Catching multiple exception types
  • Curl HTTP/2 server push support
  • Support class constant visibility
  • Void return types
  • Generalize support of negative string offsets
  • Allow specifying keys in list() and square bracket syntax for array destructuring
  • Warn about invalid strings in arithmetic
  • Deprecate and remove mcrypt()

https://medium.com/@amo.chohan/upcoming-changes-in-php-7-1-76ebea53b820#.2udxw3qfe