According to Serebii.net:
“Pokémon GO
In The Games Department
Pokémon GO - Shiny Meltan Event Repeat
It has been confirmed that Shiny Meltan to re-appear in Mystery Boxes in Pokémon GO from April 24th 20:00 UTC to May 5th 20:00 UTC. With this, Mystery Boxes will once again only need 3 days for use.”
GoHub article has yet to come but I’ll edit this post when it exists.
Nice, but doesn’t help me. You need a version of Let’s Go for a Mystery Box… I have the money, but not the time to play an other game. So no Shiny Meltans for me 
Same here. 
All the best to those who have the box and have gone to the effort to activate their Meltan-making magic. I’ve only the time for one game, and would rather just keep playing PoGo, than switch to a different game for the weeks or months it would take to activate the boxes.
Wont make not exchange the game for something better lol
I’m sure there will be interaction of new Pokémon for Sword and Shield too.
dont have one yet
Ask for a Switch for Christmas.
I have a switch
My roommate plays Lets Go, so I was lucky enough to land a 95.6% Meltan as well as a shiny last time. Good luck to those still looking!
I’ll just polish my one and only Meltan! 
Need a thousands kilometer still to walk…
Still have after evolving 3 new Melmetals last week. Holding out for good Meltans.
Doesn’t take Carnac the Magnificent to predict that I’ll skip that one, too…
^^^I’m sure most of target audience here had that reference go over their heads, but I got you.
Same. I’m old.
Holding envelope to head.
I’m glad you got reference. It’s hard now with all these new kids in the Internet.
