Several known games are normally conducting large updates once or twice a year depending on the game and community. Most of these updates match to the days they were launched. Meanwhile, these major updates were launched around 2 weeks or a month after the game was initially released.
According to the reports from Otakukart, Pokemon Go officially arrives last July. That means major updates are suspected to be launched around the same time if Niantic is planning to have one. Pokemon Go still lacks a lot of features which makes it a static game as of the moment. Apparently, all these missing features are expected to be added when Gen 2 Patch arrives since most of them occurred in Gen 2 such as Breeding and Shiny Pokemon. Furthermore, even a Friend System was launched during generation 2.
On the other hand, generation 2 has already been found in the game's code. That means it is confirmed that these new features and generation 2 Pokemon will be arriving to Pokemon Go soon. However, there is no exact release date for this major update as of now. In addition, Niantic lacks communication to their player-base. For example, Niantic has not provided any early information regarding the arrival of Valentine's Day event. As a result, fans don't have enough time to prepare for the newest event coming to Pokemon Go.
Based on the report, seeing these elements from the gen 2 patch in the game codes does not guarantee a done deal. Developers will need to conduct a series of tests to the codes before releasing them to the public in order to ensure a bug-free update. Additionally, sprites for the generation 2 Pokemon are also needed to be put in the game as well.
Lastly, there is a big possibility that the next major patch for Pokemon Go is generation 2. Meanwhile, Niantic could release several feature additions every week prior to its official launch or they could just add them all at once. Furthermore, releasing this gen 2 would surely bring back the hype for the game especially with the new added features that would motivate fans to play the game.