March 30-November 11, 2018

Research feature introduced. Trainers find they can "stack" Research Task Rewards almost infinitely. On August 7th Niantic announces a 100 encounter cap to be enforced on August 20th, however, Niantic actually enforced the cap on August 16th which was earlier than announced. As an immediate response to complaints, Niantic temporarily removed the cap on August 16th and announced a new enforcement date of August 27th. On October 4th, Niantic announces they will be restoring lost encounters, causing multiple bugs including multiple Mew and Celebi encounters, full stacks being lost, and stacks being recovered that didn't originally belong to the trainer. Restoration announced as complete on October 12th. Cap is announced again on November 8th, for implementation on November 11th.