diff --git a/modules/radix/home/services/zathura.scm b/modules/radix/home/services/zathura.scm
index abad3c8..97d07da 100644
--- a/modules/radix/home/services/zathura.scm
+++ b/modules/radix/home/services/zathura.scm
@@ -110,6 +110,9 @@
     (null? (filter (negate hex-digit?) rest)))
    (else #f)))
 
+(define serialize-hex-color              ; Just to avoid warnings
+  (@@ (gnu services configuration) empty-serializer))
+
 (define-maybe hex-color)
 
 (define-configuration/no-serialization face