diff --git a/packages/ocluster-worker/ocluster-worker.0.2.1/opam b/packages/ocluster-worker/ocluster-worker.0.2.1/opam
index 981c5cf5384c..938a2921d85e 100644
--- a/packages/ocluster-worker/ocluster-worker.0.2.1/opam
+++ b/packages/ocluster-worker/ocluster-worker.0.2.1/opam
@@ -18,7 +18,7 @@ depends: [
   "fpath"
   "logs"
   "lwt" {>= "5.6.1"}
-  "obuilder" {>= "0.5.1"}
+  "obuilder" {>= "0.5.1" & < "0.6.0"}
   "prometheus-app" {>= "1.2"}
   "odoc" {with-doc}
 ]
diff --git a/packages/ocluster/ocluster.0.2.1/opam b/packages/ocluster/ocluster.0.2.1/opam
index 4a61e50e5dc9..b2444cc8a107 100644
--- a/packages/ocluster/ocluster.0.2.1/opam
+++ b/packages/ocluster/ocluster.0.2.1/opam
@@ -34,7 +34,7 @@ depends: [
   "lwt" {>= "5.6.1"}
   "lwt-dllist"
   "mirage-crypto" {>= "0.8.5"}
-  "obuilder" {>= "0.5.1"}
+  "obuilder" {>= "0.5.1" & < "6.0.0"}
   "ppx_expect" {>= "v0.14.1"}
   "ppx_sexp_conv"
   "prometheus"