On 26 and 27 July 2026, App Store search changed. Apple announced nothing, as usual. It showed up here as a break in the distribution of iOS difficulty scores across tens of thousands of tracked keywords, on two consecutive days, and it never went back.
That is the advantage of measuring hundreds of thousands of positions a day: a store can change the rules quietly, and the data still says when.
iOS difficulty has been retuned against the new results and the full history recomputed, so a difficulty chart reads continuously across July instead of showing a step. Google Play difficulty was not affected, which is itself evidence the change was Apple's alone.
If your iOS keyword picks felt harder to read in August, this is why. The store side of the story is in Why your App Store keyword rankings dropped overnight, and the volatility is now measured daily by the algorithm change detector.