Hello, Since version 0.46-2 Xmobar uses Pango instead of XFT. This will affect what the config file will look like in the Fonts section. See Project Thread.
xft:Bitstream Vera Sans Mono:size=9:bold:antialias=true
Would now be
Bitstream Vera Sans Mono 9 Bold
As for antialiasing you will now have to edit
Quoting a response from the developer.
in principle, you can specify in your fonts config whether a font has (or not) anti-aliasing. check for instance: https://askubuntu.com/questions/32727/how-do-i-turn-off-font-pixel-antialiasing-only-in-terminal/32733#32733 (which i think nowadays lives in ~/.config/fontconfig/fonts.conf). there are many other options that you can control from there and, at least in theory (i might have bugs there), xmobar should honour them, since it's using directly the pango engine. (and no, i am afraid the xft is gone for good, and you can only use it in previous versions of xmobar, sorry about that.)
For more info on fonts see Quick start: using xmobar