Ramin,
Apparently, it’s a standalone installation and there is no upgrade path. Please reply if incorrect.
Yes you are correct. MyEclipse 2015 CI is a standalone installation and you cannot directly upgrade from MyEclipse 2014, as MyEclipse 2015 is based on Eclipse 4.4 and MyEclipse 2014 is based on Eclipse 4.3.
How one would import the settings from one installation to another?
You can import your workspace preferences but you still need to install the third party plugins in MyEclipse 2015 CI, as the base Eclispe version will be changed (since MyEclipse is based on Eclipse). For ex: MyEclipse 2013 is based on Eclipse 3.8, MyEclipse 2014 is based on Eclipse 4.3, MyEclipse 2015 is based on Eclipse 4.4.
To import your old MyEclipse workspace preferences/settings to the new MyEclipse workspace, you need to follow these steps : from your old MyEclipse workspace menu bar select File > Export. In the new window that opens go to General > Preferences > Next and follow the wizard to export your preferences to a .epf file. Similarly you can use “Import” to get all the preferences into the new MyEclipse workspace.
Let us know if you have any further questions.