In the Team rocket werehouse on five island. I forget but I think you need to fight some rocket grunts before you can get to it.
The upgrade can be found in the Team Rocket Warehouse in the Sevii Islands. You will need 2 passwords to enter, and it is found amidst other items in the floor panel puzzle that covers the majority of the warehouse.
in the trainer tower . it is a reward.
Raise to level 20.
eiquip it to porgon then trade it to get a porgon 2
you will find it on island 7 when you complete the battle tower
give it to a porygon and trade it to another person and it evolves into a porygon2
You can't unless you trade a Pokemon holding one from FR or RSE.
you have to beat the trainers and the time in that place on seven island
You must evolve Porygon (From Celadon) using the UpGrade to Porygon 2.
Porygon evolves while being traded while holding an Upgrade.
Yes you can trade leafgreen version Pokemon to another leafgreen version.
You need to trade a Porygon holding an Upgrade.You get an Upgrade from Silph Co building.
Not in Pokemon leafgreen only in Pokemon Firered never ever in Pokemon leafgreen And in Pokemon firered it is rare in power plant not available in Pokemon leafgreen?