Since Hilton’s award chart changes in 2013, there haven’t been huge additional changes.
Hilton decided to alter the way they made changes to how they re-assign hotels to award categories. Instead of an annual change to tons of hotels (a schedule they really weren’t wedded to in the past anyway) they decided they would make rolling changes throughout the year. And instead of informing all members proactively of these changes, they would just post them on a web page in the name of transparency.