Critical programming issues preventing a PHP 7 upgrade

Please share what sort of issues you had, when upgrading to PHP 7.

Hi everyone I would like to ask for some advice from this community of web developers about the problem that I am facing right now as I am personally an IT person. I hired a web developer to develop an e-commerce website for me. Yesterday I came to know that the PHP version that was used to creat the website was very old, it’s PHP 5.6. A friend of mine who a understand a thing or two about the web development, said that this web developer had you, in an ugly way thoroughly. What he meant is that the version is to old. And it’s practically useless. He said it’s impossible to upgrade it or do anything about it. He said the web developer sold me a useless website. If it’s not a problem for you guys, could you please enlighten me as how bad is my situation here, and if my friend is right. Because, though my friend understanding something about web developing but he is not a professional.

We have a php5.x 17 years old website. Our website is still running without huge errors, We just change to php5.6 (from php5.2? we are not sure )for our website scripts. Our hosting say we need to upgrade our code. We ask our hosting company how much times we have as We are not capable to do that yet. We have to spend times to learn. How much time do u think we have. We prefer the least among of changes n least amount of learning.

Thanks it help me !

The preg_split did add empty slots to the begin and end of the array.
Why?