The Upgrade Item in Pokemon GO
The upgrade item is a special evolutionary item in Pokemon GO that can make certain creatures in the pocket transform into more powerful versions. It's an important bridge to understanding the evolution process and expanding your Pokedex.
Players can upgrade their items by spinning Photo Disks at PokeStops and Gyms for seven days in a row, and also by completing event-specific Field Research tasks. However they have a low drop rate.
Porygon2 is a possible evolution item by using this item
In Pokemon Go the player can use an item called Upgrade to transform Pokemon into more powerful versions. This process requires some steps that aren't difficult to accomplish and adds an additional dimension to the game's gameplay.
One of the most distinctive Pokemon in the Pokemon franchise is Porygon, which can be evolved into Porygon2 and then into Porygon-Z. To unlock these evolutions, you'll need to possess a few items. These include the Upgrade disc and Dubious disc. These items aren't common, but not impossible to locate in the game.
The Upgrade is a very rare item used to unlock the second evolution stage for the Pokemon Porygon. To get this item, players must to capture and transfer Porygon. Each capture and transfer will yield one Candy, so it's best to collect a lot of the creatures. Trainers can also try to get this item by spinning PokeStops that have the possibility of dropping the item, along with other rewards.
The Dubious Disc is another rare item in Pokemon GO that can be used to evolve Porygon into its more powerful form. To obtain this item, players must collect 50 pieces of Porygon Candy. This can be achieved by catching Porygons and transferring them Professor Willow or walking with your Pokemon as a companion. Trainers can also try to get this rare item by spinning PokeStops, although it's a little more difficult to land on one.
It's a great way to give depth to your Pokemon GO experience. It requires a few unique items and in-game currency, but it's not terribly difficult to achieve.

Porygon unlike other Pokemon in the series, can only evolve into its final form by using an item called Upgrade. This item is extremely scarce and is only available by spinning PokeStops, or by completing research Breakthroughs. It is possible to get the item by trading a Porygon when it has the item attached or using the Special Trade Item.
This is a rare drop of level 4.
Upgrades are items that can be used to improve equipment, by adding new features. Upgrades are available in the inventory of the game, from karma sellers, or as rewards for events. They can be added as upgrades to armors, weapons, trinkets and gathering tools. Upgrades can be added to any slot on the unit. Certain upgrades require that an item of a higher level be added. The majority of upgrade components can be modified, but the previous component will be destroyed. Only a few types of upgrade are salvageable by using salvage kits that are of high quality, such as the Black Lion Salvage Kit and Ascended Salvage Tool.
Upgrades can be made by by combining an upgrade item with the item it's placed in or by rerolling the item with a rerolling token. The rerolled item has the same additional stats, but also a new tier and level. Each item has a maximum level of upgrade and a minimum item level. Upgrade levels are determined by the item's tier which is determined by its rarity and level. Each level is divided into three levels. Each level has its own upgrade costs and bonuses.
Generally upgrading an item will boost its primary stat by a fixed amount, and also provide a random extra stat. The cost of upgrading an item increases as its tier rises however, there are discounts for some items and the number of upgrades required drops with each step.
The upgrade item can be obtained by spinning Photo discs at PokeStops and Gyms but it has a low chance to be dropped every day. It is also available as a reward for a seven-day streak of spinning at minimum one PokeStop or gym Photo Disc every day, or through event-specific Research Tasks.