Pennsylvania adopted the 2015 IECC for residential and commercial buildings in October of 2018 with minimal PA-specific amendments. These amendments are actually elements taken from the 2018 IECC, which streamlines many commissioning processes, simplifies certain language, and will help with future code adoption. You can find those amendments here. Pennsylvania also has a new list of resources and toolkits along with its own website for training professionals to work and comply with its new codes. The adoption outlook for future codes is unclear but will likely look at 2018 IECC adoption around 2022, if not sooner.