When you install 2.xxx, it will install in a different sub directory and will not change the 1.187 install. It is like having two different programs installed. You can choose to run either one. The only thing is that if you open files by double clicking on file names, the 2.xxx will open (the new default). If you want to open a file in 1.187, you have to open 1.187 first and then open the file from within 1.187.