I've upgraded one of my computers to Linux Mint 18 from 17 using the steps on this page:
First i've upgraded to version 17.3 by using the menu on update manager. Than i've started upgrade process to version 18 by using the steps on previous url which took me a long time to complete (possibly bacause of internet connection problems).
I'd like to write some of the changes i see during my usage.
First of all i've noticed that PHP version has been updated to PHP 7 which was something i wanted and that was actually the main reason to upgrade Mint for me. However i'll need to make some changes to my framework to make it compatible for PHP 7.
Another change i've found is about scrolling behaviour which has been reversed in direction. When i scroll down the page content goes up as opposite to the classical behaviour of scroll on pages. But i have changed this to the normal direction by disabling the setting "Natural scrolling" on touchpad settings of control panel.
I've also discovered that there has been a change with text fonts on google chrome which may be caused by default font definitions of Linux Mint on the new version. I can also feel that the terminal font seems to have changed.
On desktop i can't actually notice a change except that texts of icons on desktop have changed color to black so that i cant see them on my previous solid black background. Text color changes to white when i set theme but this happened again the next session so i have changed the background. Let me remind that as in every new version of Linux Mint there are many more desktop images you can select from for your desktop.
You can also realize that some apps have been renamed in Linux Mint. For example Pluma has been replaced by Xed.
I'll continue updating this post as i experience new changes or problems i may have so that users who have the same problems may found it useful.