There have been a great number of other additions and improvements, but here is a short overview of the most important changes:

• Namespaces (documentation maybe out dated)
• Late static binding and __callStatic
• Lambda functions and closures
• Addition of the intl, phar (phar is scheduled for some more work a head of alpha2), fileinfo and sqlite3 extensions
• Optional cyclic garbage collection
• Optional support for the MySQLnd replacement driver for libmysql
• Windows older than Windows 2000 (Windows 98, NT4, etc.) are not supported anymore (details)
• New syntax features like NOWDOC, limited GOTO, ternary short cut "?:"

Check php.net for more details.