diff --git a/srcpkgs/eigen/template b/srcpkgs/eigen/template
index f08f538255b..f12f1a44f5a 100644
--- a/srcpkgs/eigen/template
+++ b/srcpkgs/eigen/template
@@ -1,4 +1,6 @@
 # Template file for 'eigen'
+# XXX: ceres-solver hardcodes the eigen version
+# rebuild it when updating this
 pkgname=eigen
 version=3.4.0
 revision=1