A couple of notes on upgrading from PHP 5 to PHP 7.
Firstly you can try to copy your site or code to a server with PHP 7 and see how your PHP 5 application runs and then move forward. You can also try to use a tool to help you with finding code that needs to be upgraded and reading the documentation. See the links below.
You might have a couple of issues with mailR when running on a server.
When installing or after installing the r package: rJava you might encounter the following: libjvm.so: cannot open shared object file: No such file or directory
I fixed this on a ubuntu server with this command: sudo R CMD javareconf
Appending MOV files efficiently can be a challenge. The only "safe" and easy way without destroying the video or the sound is done by using Avidemux which is a free video editing tool for Linux.
Here is my modified image-convert bash script used for the appending all .MOV files in a folder and have the full video ready for editing in the Avidemux graphical user interface (GUI).