diff --git a/thunderbird-mozconfig b/thunderbird-mozconfig
index 6358b19..c6849e3 100644
--- a/thunderbird-mozconfig
+++ b/thunderbird-mozconfig
@@ -30,6 +30,7 @@ ac_add_options --enable-gio
 ac_add_options --disable-gnomevfs
 ac_add_options --disable-gstreamer
 ac_add_options --enable-pie
+ac_add_options --with-system-icu
 
 # lightning related
 ac_add_options --enable-calendar