This is a brilliant blog post.

What happens if you write to the address listed in the GPL?

https://code.mendhak.com/gpl-v2-address-letter/

I wrote to the address in the GPLv2 license notice and received the GPLv3 license

I was curious about the 51 Franklin Street address in the GPLv2 license notice so I wrote to them as they said

@Edent How is GPLv3 different?
And why did you get it in the mail?
If I want to get it, do I have to follow the same procedure?
Can't I just copy and paste?
@universish I didn't write the blog post. Please address your queries to the author.