I believe they changed some of the number of days in the age spans. They decreased the baby, toddler, young adult and adult by 1 day in short span, decreased baby by 1 day in normal span but increased teen by 8 days and adult by 9 days. In the long span they decreased baby, young adult and adult by 8 days. The elders now have days instead of being varied as they were before. If you search for age span change in sims 4 in patch before high school years you can see the charts comparing the 2. I think doing that probably affected some of the ages in the game of those sims we already had. I assume they did it to give teens a longer life span for the pack. I usually play with aging off so hopefully this new change won't affect my sims.