Study easy PHP 2.0 here : http://52.53.55.151:11514/

https://realworld-ctf-2019-quals.s3-us-west-1.amazonaws.com/184c379a6f90b9e3fcbbdf3f57d8a388/Master_of_PHP.zip

hint: You can find the corresponding commit version on github according to the modification time of the file.