An Upgrade is a rare evolution item in Pokemon GO that is required to evolve Porygon to Porygon2. If you're looking to evolve the Virtual Pokemon, here's a guide explaining how you can get your hands on an Upgrade.
Porygon is a Normal-type Pokemon, and one of the hardest Pokemon to evolve in Pokemon GO. Trainers will need an Upgrade and 25 Candy to evolve Porygon to Porygon2, and then a Sinnoh Stone and 100 Candy to evolve Porygon2 to Porygon-Z. Currently, Porygon is the only Pokemon that requires an Upgrade to evolve, but there's a chance Niantic will add more Pokemon that need an Upgrade later.
How to Get an Upgrade in Pokemon GO
The main way Trainers can obtain Upgrades is by spinning PokeStops. There is a 1% chance that every time you spin a PokeStop, an evolution item like an Upgrade or Sinnoh Stone will drop. That makes getting the specific item you want even harder.
Luckily, Niantic implemented a feature where Trainers are guaranteed to receive an evolution item on their seven-day streak of spinning a PokeStop. Make sure to spin PokeStops every day, so you have a chance at obtaining an Upgrade each week.
Currently, Trainers can also receive an Upgrade by completing a Timed Research chain, Ultra Unlock 2021: Time. On Step 4 of the research chain, you'll find the mission "Catch 7 Porygon", which rewards you with an Upgrade. Porygon are spawning more frequently in the wild during this event, so now is a great time to catch some Porygon and get the Upgrade you need for its evolution.
Once you evolve your Porygon, you'll need a Sinnoh Stone to evolve it further, so check out our guide on how to get one. If you're looking for more evolution items, check out our guides on the Metal Coat or the Sun Stone.