I have built upon software that is released under GPLv2 (with the 'at your option, a later version' addition), and am now conveying that software to my client under GPLv3. Of course, I provide the full source code with the software.
I'm also assigning the copyright of the work to the client. The client may or may not decide to publicly distribute this software.
If they don't publicly distribute the software, would I still be considered to have been 'conveyed' the software, and thus I could still make use of it in line with the license?
Or, since I assigned copyright to the client, do I also have to destroy my copies of the software and wait for them to convey it back to me (or publicly release it) before I can use the software again?