diff --git a/config/config.go b/config/config.go
index 792ef5c1b0..419c26a945 100644
--- a/config/config.go
+++ b/config/config.go
@@ -117,7 +117,7 @@ var (
 	DefaultAlertmanagerConfig = AlertmanagerConfig{
 		Scheme:           "http",
 		Timeout:          model.Duration(10 * time.Second),
-		APIVersion:       AlertmanagerAPIVersionV1,
+		APIVersion:       AlertmanagerAPIVersionV2,
 		HTTPClientConfig: config.DefaultHTTPClientConfig,
 	}
 
diff --git a/config/config_test.go b/config/config_test.go
index 61ef13ac86..b2ae0343f1 100644
--- a/config/config_test.go
+++ b/config/config_test.go
@@ -785,7 +785,7 @@ var expectedConf = &Config{
 			{
 				Scheme:           "https",
 				Timeout:          model.Duration(10 * time.Second),
-				APIVersion:       AlertmanagerAPIVersionV1,
+				APIVersion:       AlertmanagerAPIVersionV2,
 				HTTPClientConfig: config.DefaultHTTPClientConfig,
 				ServiceDiscoveryConfigs: discovery.Configs{
 					discovery.StaticConfig{
diff --git a/docs/configuration/configuration.md b/docs/configuration/configuration.md
index 3173279a29..2684eadadd 100644
--- a/docs/configuration/configuration.md
+++ b/docs/configuration/configuration.md
@@ -1755,7 +1755,7 @@ through the `__alerts_path__` label.
 [ timeout: <duration> | default = 10s ]
 
 # The api version of Alertmanager.
-[ api_version: <string> | default = v1 ]
+[ api_version: <string> | default = v2 ]
 
 # Prefix for the HTTP path alerts are pushed to.
 [ path_prefix: <path> | default = / ]
diff --git a/notifier/notifier_test.go b/notifier/notifier_test.go
index 432e07f86b..ea0b7b1519 100644
--- a/notifier/notifier_test.go
+++ b/notifier/notifier_test.go
@@ -454,7 +454,7 @@ func TestReload(t *testing.T) {
 					},
 				},
 			},
-			out: "http://alertmanager:9093/api/v1/alerts",
+			out: "http://alertmanager:9093/api/v2/alerts",
 		},
 	}
 
@@ -504,7 +504,7 @@ func TestDroppedAlertmanagers(t *testing.T) {
 					},
 				},
 			},
-			out: "http://alertmanager:9093/api/v1/alerts",
+			out: "http://alertmanager:9093/api/v2/alerts",
 		},
 	}