diff --git a/infra/bots/gen_tasks.go b/infra/bots/gen_tasks.go
index 63dbe821f9..d4608c4010 100644
--- a/infra/bots/gen_tasks.go
+++ b/infra/bots/gen_tasks.go
@@ -438,7 +438,7 @@ func defaultSwarmDimensions(parts map[string]string) []string {
 		}
 		if d["os"] == DEFAULT_OS_MAC && (parts["model"] == "MacBook10.1" || parts["model"] == "MacBookAir7.2") {
 			// TODO(dogben): Get all Mac bots on the same version.
-			d["os"] = "Mac-10.13.5"
+			d["os"] = "Mac-10.13.6"
 		}
 	} else {
 		d["os"] = DEFAULT_OS_DEBIAN
diff --git a/infra/bots/tasks.json b/infra/bots/tasks.json
index 9377e0d650..683699b86e 100644
--- a/infra/bots/tasks.json
+++ b/infra/bots/tasks.json
@@ -28711,7 +28711,7 @@
       ],
       "dimensions": [
         "gpu:8086:591e",
-        "os:Mac-10.13.5",
+        "os:Mac-10.13.6",
         "pool:Skia"
       ],
       "env_prefixes": {
@@ -28823,7 +28823,7 @@
       ],
       "dimensions": [
         "gpu:8086:591e",
-        "os:Mac-10.13.5",
+        "os:Mac-10.13.6",
         "pool:Skia"
       ],
       "env_prefixes": {
@@ -28935,7 +28935,7 @@
       ],
       "dimensions": [
         "gpu:8086:591e",
-        "os:Mac-10.13.5",
+        "os:Mac-10.13.6",
         "pool:Skia"
       ],
       "env_prefixes": {
@@ -29047,7 +29047,7 @@
       ],
       "dimensions": [
         "gpu:8086:1626",
-        "os:Mac-10.13.5",
+        "os:Mac-10.13.6",
         "pool:Skia"
       ],
       "env_prefixes": {
@@ -29159,7 +29159,7 @@
       ],
       "dimensions": [
         "gpu:8086:1626",
-        "os:Mac-10.13.5",
+        "os:Mac-10.13.6",
         "pool:Skia"
       ],
       "env_prefixes": {
@@ -29271,7 +29271,7 @@
       ],
       "dimensions": [
         "gpu:8086:1626",
-        "os:Mac-10.13.5",
+        "os:Mac-10.13.6",
         "pool:Skia"
       ],
       "env_prefixes": {
@@ -54804,7 +54804,7 @@
       ],
       "dimensions": [
         "gpu:8086:591e",
-        "os:Mac-10.13.5",
+        "os:Mac-10.13.6",
         "pool:Skia"
       ],
       "env_prefixes": {
@@ -54916,7 +54916,7 @@
       ],
       "dimensions": [
         "gpu:8086:591e",
-        "os:Mac-10.13.5",
+        "os:Mac-10.13.6",
         "pool:Skia"
       ],
       "env_prefixes": {
@@ -55028,7 +55028,7 @@
       ],
       "dimensions": [
         "gpu:8086:591e",
-        "os:Mac-10.13.5",
+        "os:Mac-10.13.6",
         "pool:Skia"
       ],
       "env_prefixes": {
@@ -55140,7 +55140,7 @@
       ],
       "dimensions": [
         "gpu:8086:591e",
-        "os:Mac-10.13.5",
+        "os:Mac-10.13.6",
         "pool:Skia"
       ],
       "env_prefixes": {
@@ -55252,7 +55252,7 @@
       ],
       "dimensions": [
         "gpu:8086:1626",
-        "os:Mac-10.13.5",
+        "os:Mac-10.13.6",
         "pool:Skia"
       ],
       "env_prefixes": {
@@ -55364,7 +55364,7 @@
       ],
       "dimensions": [
         "gpu:8086:1626",
-        "os:Mac-10.13.5",
+        "os:Mac-10.13.6",
         "pool:Skia"
       ],
       "env_prefixes": {
@@ -55476,7 +55476,7 @@
       ],
       "dimensions": [
         "gpu:8086:1626",
-        "os:Mac-10.13.5",
+        "os:Mac-10.13.6",
         "pool:Skia"
       ],
       "env_prefixes": {