How to fix the prev/next arrows image

After updating out WordPress installation and changing some fonts we’ve got some strange images instead of arrows on next/previous posts:  (U+F430) and  (U+F429).

These images are utf-8 characters in the Private Use Unicode subset.

In CSS these arrows are defined as ‘\f430’ and ‘\f429’:

.single #content #nav-below .nav-next a:before {
   content: '\f430';
}
.single #content #nav-below .nav-previous a:after {  
   content: '\f429';
}

So, if you see these images instead of arrows, then you got another character representation than you need. The easy solution is to add a Genericons font-family tag to your css:

.single #content #nav-below .nav-next a:before {
   content: '\f430';
   font-family: Genericons;
}
.single #content #nav-below .nav-previous a:after {
   content: '\f429';
   font-family: Genericons;
}