Upgrading the operating system won't change the program. (Although you may need to uninstall/reinstall the program after you go to Windows 10). So, if you've started your project in Premiere Elements 11 on Windows 8, you can finish it in Premiere Elements 11 on Windows 10.
I would recommend against opening a project created in one version of the program with another version of the program -- as in opening a project begun in version 11 with version 14. If often can lead to buggy behavior and, in some cases, total corruption of your project file.
PE 11 was released a long time ago. Are you 100% sure it will be compatible with Windows 10?
Also, is PE 14 much better than PE 11?
Would you recommend to upgrade PE 11 to the latest version of PE?
Premiere Elements 10, 11, 12, 13 and 14 all run fine on my Windows 10. Worst case is you may have to run it in XP compatibility mode.
It shouldn't be necessary to upgrade.
Thank you Steve.
Do you consider PE 14 much better than the previous versions?
It makes sense to upgrade to PE to the latest version.
I will wait for a few more months and upgrade PE 11 to PE15. :-)