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 gives me flashbacks to a time I had to (while helping my dad fix a printer issue) dial long distance from Canada to California into some BBS-like system to get updated drivers because the internet basically didn’t exist yet or HP didn’t have drivers up at the time. Luckily it worked and didn’t cost too much. It all seems like a dream now.