The difference between GPX1.0 and GPX 1.1
GPX is the extension of a file for your navigation system. You can compare this abbreviation with the .docs extension of a Word file. The extension of a file can therefore tell you what type of file it is.
GPX 1.1 can be seen as an 'updated' and 'improved' version of GPX1.0. A GPX 1.1 file can contain more information and therefore transfer to your navigation system. All new navigation systems can read a GPX 1.1 file. Older navigation systems cannot understand this 'more complicated' file type and therefore you still export a GPX1.0 file to older systems.