There are two changes made to the Amazon Associates Agreement for UK and EU affiliates.
The first is a change in how you can close your account if there is no activity after 3 years. This is a slight change to the existing policy.
The second is a table of revised commission rates for all locations. This means that the commission rate could be increasing or decreasing for your niche.
There are many changes in the commission rate, so please check the following link to see all the details that apply to you:
Keep in mind that this link is likely to be temporary. If you are viewing it after May 1, 2016, it may now reflect different changes in the Amazon Associates Agreement.
You can check the most recent agreement within your Amazon Associates account.