License to tie to an extended version of an accepted paper while submitting to ArXiv?
Let me expand my comment, since I think it was misinterpreted. Suppose you produce some work and license it with a permissive license. In the future, you can relicense that work with an even more permissive one, but not a more restrictive one. People can rely on the earlier permissive license for that work, but only for that work. 

However, if you produce a new work, you can license that however you wish, or not at all. You can even put "Copyright - all rights reserved" on the new work. But that doesn't change the license to the old one. Anyone relying on only the older work can rely on its original license. But if someone wants to use the new work somehow, they have to abide by its license (or lack thereof). Of course the two works would need to be sufficiently different for this to have any real meaning. 

For example you could publish a textbook under a Creative Commons license (CC-BY-SA, say) and then a second edition with all rights reserved. The first edition still has its permissive license. Only the material in the second has the restrictive license. 

Note that I am not a lawyer. But the basic idea is that you can't "lock up" IP once you make it available, but you can make it more available if you like. 

And, in general, a work that isn't specifically licensed is considered in many (most?) places to be copyrighted. But laws do differ. 

So, your best option is to be explicit about the new work's license. 



An example, sparked by a now deleted comment:

UC Berekely created a version of UNIX, the BSD (Berkeley Software Distribution) with its own permissive license. Apple built OS X (macOS) on top of BSD and used many of its elements. But macOS does not have a permissive license, but a restrictive one (or none - all rights reserved - proprietary software). But Apple didn't "lock up" BSD and anyone can still depend on that original license for their own work. But the copyright holders of BSD cannot, now, put more restrictions on their own license that would, now, invalidate OS X. They could, however, make it even more permissive.