diff --git a/dune-project b/dune-project
index 9e4bf68..29d10e8 100644
--- a/dune-project
+++ b/dune-project
@@ -49,6 +49,10 @@
     :with-test
     (>= v0.16)
     (< v0.17)))
+  (ppx_fields_conv
+   (and
+    (>= v0.16)
+    (< v0.17)))
   (ppx_hash
    (and
     (>= v0.16)
diff --git a/loc.opam b/loc.opam
index 111f6fa..4d69033 100644
--- a/loc.opam
+++ b/loc.opam
@@ -17,6 +17,7 @@ depends: [
   "ppx_compare" {>= "v0.16" & < "v0.17"}
   "ppx_enumerate" {>= "v0.16" & < "v0.17"}
   "ppx_expect" {with-test & >= "v0.16" & < "v0.17"}
+  "ppx_fields_conv" {>= "v0.16" & < "v0.17"}
   "ppx_hash" {>= "v0.16" & < "v0.17"}
   "ppx_here" {>= "v0.16" & < "v0.17"}
   "ppx_js_style" {>= "v0.16" & < "v0.17"}