The $additional_headers parameter of mail() and mb_sendmail() now also accepts an array instead of a string.
The DBA extension now has support for LMDB.
--with-pdo-ociconfigure argument no longer needs the version number of the Oracle Instant Client.
--enable-gd-native-ttfconfigure argument has been removed. This was not used since PHP 5.5.0.
--with-config-profileconfigure argument has been added. This can be used to save specific configures, much like the magical config.nice.bat file.
The MCrypt extension has now been moved out of the core to PECL. Given the mcrypt library has not seen any updates since 2007, its usage is highly discouraged. Instead, either the OpenSSL or Sodium extension should be used.