diff --git a/ovni.c b/ovni.c
index fc0c863..2f6d01b 100644
--- a/ovni.c
+++ b/ovni.c
@@ -167,6 +167,19 @@ proc_set_app(int appid)
 		die("json_object_set_number for app_id failed\n");
 }
 
+static void
+proc_set_version(void)
+{
+	JSON_Object *meta = json_value_get_object(rproc.meta);
+
+	if(meta == NULL)
+		die("json_value_get_object failed\n");
+
+	if(json_object_set_number(meta, "version", OVNI_METADATA_VERSION) != 0)
+		die("json_object_set_number for app_id failed\n");
+}
+
+
 void
 ovni_proc_set_rank(int rank, int nranks)
 {
@@ -246,6 +259,7 @@ ovni_proc_init(int app, const char *loom, int pid)
 
 	rproc.ready = 1;
 
+	proc_set_version();
 	proc_set_app(app);
 }
 
diff --git a/ovni.h b/ovni.h
index c0617ab..e27f298 100644
--- a/ovni.h
+++ b/ovni.h
@@ -40,6 +40,8 @@ extern "C" {
 /* Hardcode the JSON_Value to avoid a dependency with janson */
 typedef struct json_value_t  JSON_Value;
 
+#define OVNI_METADATA_VERSION 1
+
 #define OVNI_TRACEDIR "ovni"
 #define OVNI_MAX_HOSTNAME 512
 
diff --git a/trace.c b/trace.c
index 2eb8304..f79b47d 100644
--- a/trace.c
+++ b/trace.c
@@ -124,6 +124,29 @@ load_proc_metadata(struct ovni_eproc *proc, int *rank_enabled)
 	}
 }
 
+static void
+check_metadata_version(struct ovni_eproc *proc)
+{
+	JSON_Object *meta = json_value_get_object(proc->meta);
+	if(meta == NULL)
+		die("check_metadata_version: json_value_get_object() failed\n");
+
+	JSON_Value *version_val = json_object_get_value(meta, "version");
+	if(version_val == NULL)
+	{
+		die("process %d is missing attribute \"version\" in metadata\n",
+				proc->pid);
+	}
+
+	int version = (int) json_number(version_val);
+
+	if(version != OVNI_METADATA_VERSION)
+	{
+		die("pid %d: metadata version mismatch %d (expected %d)\n",
+				proc->pid, version,
+				OVNI_METADATA_VERSION);
+	}
+}
 
 static int
 load_proc(struct ovni_eproc *proc, struct ovni_loom *loom, int index, int pid, char *procdir)
@@ -156,6 +179,8 @@ load_proc(struct ovni_eproc *proc, struct ovni_loom *loom, int index, int pid, c
 		return -1;
 	}
 
+	check_metadata_version(proc);
+
 	/* The appid is populated from the metadata */
 	load_proc_metadata(proc, &loom->rank_enabled);