Sometimes you have to test your code on different php versions.
There are multiple solutions to do this:
- You can setup different php versions on your local (maybe virtual) machine and test every version one by one.
- You can run a code analyser in your ide to find problems.
And you can test easily some (critical) parts of your application in a nice online editor like:
The fun stuff is that you see exactly what every version will output or what kind of errors are thrown. Also hhvm is supported.
Here is an screen from the website about a json_decode example (link below the image)