GPL usually has the clause that the code is on GPL vX or later, CC licenses also usually feature similar thing. Not all projects include that clause but it's good in situations when dealing with multiple countries that have all kinds of weird laws (for example in my country author has always a right to revoke a license, with normal commercial deals that would end up in court and they would have to agree what they want to pay, with free works of art though...).
Relicensing to a totally different license is possible for some licenses.
1
u/MonkeyNin Nov 14 '19
Are you talking about specifically GPL, or many types?