The key features for this release (at least the ones that went through the RFC process):

Large language changes:

- Generators and coroutines (https://wiki.php.net/rfc/generators)
finally blocks (https://wiki.php.net/rfc/finally)

Syntactic sugar:

- Support for function calls in empty() (https://wiki.php.net/rfc/empty_isset_exprs)
- Support for list() in foreach (https://wiki.php.net/rfc/foreachlist)
- Constant array/string dereferencing (https://wiki.php.net/rfc/constdereference)

Standard library:

- Simplified password hashing API (https://wiki.php.net/rfc/password_hash)
- hash_pbkdf2() function (https://wiki.php.net/rfc/hash_pbkdf2)

Key anti-features (aka BC breaks):

- Dropped Windows XP and 2003 support
- preg_replace /e modifier deprecated (https://wiki.php.net/rfc/remove_preg_replace_eval_modifier)
- Logo GUIDs removed

Download from here: http://downloads.php.net/dsp/