更新到最新版本
    PHP, like any other large system, is under constant scrutiny and
    improvement. Each new version will often include both major and
    minor changes to enhance and repair security flaws, configuration
    mishaps, and other issues that will affect the overall security
    and stability of your system.
   
    Like other system-level scripting languages and programs, the best
    approach is to update often, and maintain awareness of the latest
    versions and their changes.