HHVM 4.40 release, only supports Hack language PHP virtual machine

HHVM 4.40 release, this release marks the termination of the support of 4.33, still support HHVM 4.34-4.39, as well as 4.8 and 4.32 LTS version.

This version has a disruptive change:

• XHP same two specified properties (<foo x = "1" x = "2" />) is now a syntax error

The characteristics of last year's changes inadvertently allow the parser to accept XHP  childrenany type of statement, however:

• XHP library still does not support this feature.
• Type checker does not verify children.
• This may result in unsatisfactory children statement, for example, a reference to an undefined type.

Currently change the type checker to verify XHP childrenstatement undefined type is not referenced; XHP in  childrenthe case statement, the following types will be considered valid type checker:

• Sensitive to distinguish special value pcdata, anyor empty.
• XHP category name, for example %foo.
• Defined unaliased, non-Hack generic type, class name, for example, XHP class or interface.

This change may appear in the 4.41 version, review the details update:

https://hhvm.com/blog/2020/01/13/hhvm-4.40.html

HHVM originally by the Facebook PHP to create a virtual machine, but it will greatly increase the speed of PHP code by dynamically translated into native machine code. HHVM support PHP and PHP Hack language dialects, but the 4.0 version, only supports Hack language.