The standalone Edit Annotations window is gone. In Edit PDF mode, clicking an annotation shows a compact property row under it: color (with color swatches), opacity, border, font, icon, line endings, contents that you edit inline, and Delete. A floating list shows the document’s annotations with a filter box, lets you select several (Shift/Ctrl+click), and has Delete, Discard changes and Save buttons. Ctrl + click an annotation to turn on Edit PDF mode and select it. The toggle command is now CmdToggleEditPDF.

Choosing File Attachment from the Edit PDF toolbar or the command palette works like stamps and carets: the icon follows the cursor, and you click to place it.

The home page has a command palette button to the left of the SumatraPDF title and a ? keyboard shortcuts button to the right of it. You can drag the Keyboard Shortcuts window to move it.