Foursquare button has to be updated.

[ChALkeR]

The logo and colors of Foursquare were changed.
Their mobile applications are already updated.

https://ru.foursquare.com/about/logos

Foursquare Brand Guide PDF — https://playfoursquare.s3.amazonaws.com/press/foursquare-brandguide.pdf

Primary colors (order preserved as it is in pdf):
FS Watermelon — #F94877
FS Navy — #0732A2
FS Blue — #2D5BE3

Logo EPS:
https://playfoursquare.s3.amazonaws.com/press/2014/foursquare-logomark.eps
https://playfoursquare.s3.amazonaws.com/press/2014/foursquare-logomark-white.eps

As I understood from the PDF, you should use either FS Watermelon (#F94877) backround and white logo, or white/light gray backround and FS Watermelon (#F94877) logo.

See FortAwesome/Font-Awesome#4077 for the new logo request.

[ChALkeR]

The colors should be changed only when Font Awesome will be updated, mixing new colors with old icons would be not nice.

[ChALkeR]

when Font Awesome will be updated

The Foursquare logo should be updated in Font Awesome 4.1.1.

[ChALkeR]

The logo has been updated in a just-released version of Font Awesome (4.2.0).
Could you update the color, please?

To make things even more correct, there should be a version (e.g. 4.6.2) that depends on Font Awesome >=4.0.0 <4.2.0 and has the old color, and a new version (e.g. 4.7.0) that denends on Font Awesome >=4.2.0 and has the new color.

[ChALkeR]

Thanks!