Evidence suggests that the 1960 reprint has been somewhat "modernized", and that the undated reprint is a better match for the original 1920 printing.

Therefore, when the volumes differ, edition 11 more closely follows the undated reprint.
In edition 11, underscores are used to denote words and phrases italicized for emphasis.
There is a section of text in book 2, chapter 3, beginning with "When Vanity kissed Vanity," which is referred to as "poetry" but is formatted as prose.
I considered, but decided against introducing an 8-bit version of edition 11, in large part because the bulk of the 8-bit usage (as found in the 1960 reprint) consists of words commonly used in their 7-bit form: Aeschylus blase cafe debut debutante elan elite Encyclopaedia matinee minutiae paean regime soupcon unaesthetic Less-commonly-used 8-bit word forms in this book include: anaemic bleme coeur manoeuvered mediaevalist tete-a-tete and the name "Borge"..