IN THIS APPENDIX
Ninety-five percent of PHP 5 is backward-compatible to PHP 4. Eighty percent of website owners do not have to change a thing on their PHP 4 website to make it run with the new version. Seventy-five percent of authors make up statistics.
However, some changes in PHP 5 require a little effort to make old code run. But have no fear; there are only a few points you have to check, and they are all discussed in this chapter. We do not focus on new features, but on what it takes to migrate a PHP 4 system/application to PHP 5.
Installing PHP 5 itself is covered in depth in Appendix A, “Installing ...