2.14.2 decreased letter spacing interval
Upgrade from 2.14.0 to 2.14.2 result in noticeable decrease of letter spacing interval, at least in urxvt. I'm using monospace D2Coding font patched with Nerd icons. In urxvt this fontconfig upgrade result in increase of $COLUMNS from 100 to 106 for same urxvt window size just because of decreased letter spacing. To me text became harder to read because of this change.
I'm not sure is this a fontconfig feature/bug/misconfiguration or a font issue.
Let me know if you'll need more information/screenshots/etc.