diff --git a/manifests/config.pp b/manifests/config.pp
index 47c11c2e6..749cf0e54 100644
--- a/manifests/config.pp
+++ b/manifests/config.pp
@@ -21,7 +21,7 @@
 
   $init_defaults = {
     'MAX_OPEN_FILES' => '65535',
-  }.merge($elasticsearch::init_defaults)
+  } + $elasticsearch::init_defaults
 
   if ($elasticsearch::ensure == 'present') {
     file {
@@ -164,12 +164,7 @@
     # }
 
     # Generate Elasticsearch config
-    $data = merge(
-      $elasticsearch::config,
-      { 'path.data' => $elasticsearch::datadir },
-      { 'path.logs' => $elasticsearch::logdir },
-      $_tls_config
-    )
+    $data = $elasticsearch::config + { 'path.data' => $elasticsearch::datadir } + { 'path.logs' => $elasticsearch::logdir } + $_tls_config
 
     file { "${elasticsearch::configdir}/elasticsearch.yml":
       ensure  => 'file',
diff --git a/metadata.json b/metadata.json
index 62054b7b1..12f875207 100644
--- a/metadata.json
+++ b/metadata.json
@@ -22,7 +22,7 @@
     },
     {
       "name": "puppetlabs/stdlib",
-      "version_requirement": ">= 4.13.0 < 10.0.0"
+      "version_requirement": ">= 9.0.0 < 10.0.0"
     }
   ],
   "operatingsystem_support": [