+By default, LyX 2.3 forces output of all en and em dashes as -- and ---
+when exporting to LaTeX. This can lead to incorrect line breaks, wrong
+characters in typewriter fonts, and problems with some LaTeX packages.
+Unselect "Document->Settings->Fonts->Output em- and en-dash as ligatures"
+to keep the LyX 2.2 behaviour and avoid these problems. See chapter 3.9.1.1
+"Dashes and line breaks" of the User Guide for details.
+
+ZWSP characters (u200b) following literal em- and en-dashes are deleted by
+lyx2lyx when converting to 2.3 format. If you used them as optional line
+breaks after dashes, convert them to space insets before opening your
+document with LyX 2.3 or the optional line breaks will be lost!
+