On my 2024 Kindle Paperwhite Signature this update changes:
1) Long-press word behaviour of sideloaded books and send-to documents to match that of purchased books - the top/bottom of screen UI, and no "open dictionary" option.
2) Another long-press change is you can now pin a number of looked up words in documents (but not books) which presents an always-on icon in the bottom right.
3) Also, on some books the word(s) selection indicator is different and a bit confusing; instead of just a start/end "circle with a line" it's..uh...there's a circle at the top right of the start line of the selection and at the bottom left of the lower extent of the selection but if you want to expand the selection you press on the cursor (small vertical line) at the end of the selection or the end of the line above the start of the selection (no cursor or circle - just where the line ends - not an obviously selectable element).... it's hard to believe this isn't a bug but I just restarted the kindle and tried this on purchased and sideloaded books plus documents and it's consistent. Is anyone else seeing this?
Here's an example from a azw3 book I created (from web articles) and sent via calibre via usb:
4) Page numbers haven't come back