Let's say I create a CC BY 4.0 work today, and others contribute to it under the same license. Some individual elements will have multiple authors, some will have single authors. Some might include CC BY 4.0 elements from other sources. Some might include elements with earlier CC BY licenses.
All elements will have a statement similar to Stack Exchange, something along the lines of: "User contributions licensed under CC BY 4.0 with [attribution required]."
When CC BY 5.0 is released, I want to simply update that statement to say "CC BY 5.0". How can I achieve this?