When adding new versions, the URL will remain the same as the original piece of content.
For example, if I add a file called 'a test file.txt' to a folder called 'myfolder', the URL will read something like '/myfolder/atestfiletxt'. If I then add a new version with a different name, such as 'a different test file.txt', the URL will still read '/myfolder/atestfiletxt'.
If the URL name is something you need to change, deleting the file and re-adding it with the new name would be the best option.
I hope this helps, please let me know if you have any additional questions.