It has been two months since the last update, so Niantic will be doing their two monthly refresh of research breakthrough rewards, field research tasks and changing the Pokemon Go egg pool.
May research breakthrough rewards
During March and April there have been an abundance of legendary Pokemon that you may have been rewarded with for obtaining your seven research stamps. Specifically, these included: Entei, Raikou, Suicune, Ho-Oh, Lugia, Regirock, Regice, and Registeel.
Seven is a particularly high number of potential rewards and the upcoming change will see this drop to four. Throughout May and June, the Pokemon Go research breakthrough rewards will include Ho-Oh, Lugia, Latias, and Latios.
This is the first time the Eon Pokemon have been available outside of raid battles. Conversely, Ho-Oh and Lugia have been available for a while now.
It is interesting that the Regi-Pokemon were only available for just one research breakthrough window. This is perhaps evidence that they weren't overly popular. New encounters will begin on May 1 and last until the end of June, much like the last two sets of breakthrough rewards.
May egg pool
Along with new research breakthrough rewards, comes changes to the Pokemon Go egg pool. This new egg pool will be available from April 26 at 1 pm PDT (9 pm BST/4 pm EDT).
2km egg pool
The 2km egg pool is particularly interesting as the Gen 4 starter Pokemon are available. You'll be able to hatch Turtwig, Chimchar, and Piplup. While these Pokemon have been available in the wild since 2018, this presents an additional opportunity to catch them and accrue some much-needed candy.
Bonsly is the other confirmed 2km egg hatch and there will be others which are yet to be announced.
5km egg pool
The 5km egg pool has an unmistakable Gen 4 theme to it. Six of the seven confirmed Pokemon come from the Sinnoh region. These include Combee, Buizel, Glameow, Bronzor, Skorupi, and Croagunk.
Cubone makes up the other confirmed Pokemon with the promise of "many more" as well.
10km egg pool
Mawile, Absol, Shinx, Cranidos, Shieldon, and Riolu make up the confirmed 10km egg pool entrants. As with the other Pokemon throughout these egg pools, these have all been available previously.
Specific field research tasks for May onward have yet to be revealed. When they are, we'll have the full list and what rewards they bring.
Specific Pokemon Go field research tasks for May onward will be listed when they are made available.