PHP7.1

Till now, the preceding features that we discussed were PHP7.0 related. However, the recent version of PHP7 is PHP7.1, so it is worth discussing the important features of PHP7.1 as well, at least the features which we will use, or features that are worth knowing and using somewhere in our work.
In order to run the following code, you need to have PHP7.1 installed so, to do this, you can use the following commands:

sudo add-apt-repository ppa:ondrej/php

sudo apt-get update

(optional) sudo apt-get remove php7.0

sudo apt-get install php7.1 (from comments)

Remember that this is not an official upgrade path. The PPA is well-known, and is relatively safe to use.