These features include:
Integrate OpCache (OPcache can improve the execution speed of PHP programs by caching and optimizing PHP opcode)
Improve support for 64-bit environments
Support Unicode
Clean up internal API
Improvement Code quality, achieve Warning-Free
Improve OPcodes, compiler, runtime
JIT compiler (LibJIT?)
Support Annotation (annotation?)
Named argument (Named argument)
Different levels of type hints
Support HTTP 2.0 protocol (nghttp2 may be used to avoid reinventing the wheel)
Reliable and friendly RNG API
New Getter/Setter
C++ usage
New Encryption extension
Bundled with PECL’s http library