diff --git a/tools_webrtc/ios/tryserver.webrtc/ios32_sim_ios9_dbg.json b/tools_webrtc/ios/tryserver.webrtc/ios32_sim_ios9_dbg.json
index 8eeece96ff..29a113d413 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios32_sim_ios9_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios32_sim_ios9_dbg.json
@@ -2,7 +2,7 @@
   "comments": [
     "Tests for 32-bit iOS simulators."
   ],
-  "xcode build version": "9C40b",
+  "xcode build version": "10l232m",
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "is_component_build=false",
@@ -21,14 +21,9 @@
       "device type": "iPhone 5",
       "os": "9.3",
       "dimensions": [
-        {
-          "os": "Mac-10.12",
-          "pool": "Chrome"
-        },
-        {
-          "os": "Mac-10.13",
-          "pool": "Chrome"
-        }
+        { "os": "Mac-10.13.4", "pool": "Chrome" },
+        { "os": "Mac-10.13.5", "pool": "Chrome" },
+        { "os": "Mac-10.13.6", "pool": "Chrome" }
       ]
     }
   ]
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios10_dbg.json b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios10_dbg.json
index 5e98758ae0..6484ca1050 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios10_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios10_dbg.json
@@ -2,7 +2,7 @@
   "comments": [
     "Tests for 64-bit iOS simulators."
   ],
-  "xcode build version": "9C40b",
+  "xcode build version": "10l232m",
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "is_component_build=false",
@@ -20,16 +20,10 @@
       "include": "common_tests.json",
       "device type": "iPhone 6s",
       "os": "10.3",
-      "xcode build version": "8E3004b",
       "dimensions": [
-        {
-          "os": "Mac-10.12",
-          "pool": "Chrome"
-        },
-        {
-          "os": "Mac-10.13.3",
-          "pool": "Chrome"
-        }
+        { "os": "Mac-10.13.4", "pool": "Chrome" },
+        { "os": "Mac-10.13.5", "pool": "Chrome" },
+        { "os": "Mac-10.13.6", "pool": "Chrome" }
       ]
     }
   ]
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios11_dbg.json b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios11_dbg.json
index c145ddaf40..b54f212acb 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios11_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios11_dbg.json
@@ -2,7 +2,7 @@
   "comments": [
     "Tests for 64-bit iOS simulators."
   ],
-  "xcode build version": "9C40b",
+  "xcode build version": "10l232m",
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "is_component_build=false",
@@ -19,16 +19,11 @@
     {
       "include": "common_tests.json",
       "device type": "iPhone 7",
-      "os": "11.0",
+      "os": "11.4",
       "dimensions": [
-        {
-          "os": "Mac-10.12",
-          "pool": "Chrome"
-        },
-        {
-          "os": "Mac-10.13",
-          "pool": "Chrome"
-        }
+        { "os": "Mac-10.13.4", "pool": "Chrome" },
+        { "os": "Mac-10.13.5", "pool": "Chrome" },
+        { "os": "Mac-10.13.6", "pool": "Chrome" }
       ]
     }
   ]
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios9_dbg.json b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios9_dbg.json
index 2c0d62be4c..fdfa7b382d 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios9_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios9_dbg.json
@@ -2,7 +2,7 @@
   "comments": [
     "Tests for 64-bit iOS simulators."
   ],
-  "xcode build version": "9C40b",
+  "xcode build version": "10l232m",
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "is_component_build=false",
@@ -21,14 +21,9 @@
       "device type": "iPhone 6s",
       "os": "9.3",
       "dimensions": [
-        {
-          "os": "Mac-10.12",
-          "pool": "Chrome"
-        },
-        {
-          "os": "Mac-10.13",
-          "pool": "Chrome"
-        }
+        { "os": "Mac-10.13.4", "pool": "Chrome" },
+        { "os": "Mac-10.13.5", "pool": "Chrome" },
+        { "os": "Mac-10.13.6", "pool": "Chrome" }
       ]
     }
   ]
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios_arm64_dbg.json b/tools_webrtc/ios/tryserver.webrtc/ios_arm64_dbg.json
index a718b7acad..7594cd2a36 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios_arm64_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios_arm64_dbg.json
@@ -2,7 +2,7 @@
   "comments": [
     "Builder for 64-bit devices."
   ],
-  "xcode build version": "9C40b",
+  "xcode build version": "10l232m",
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "ios_enable_code_signing=false",
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios_arm64_rel.json b/tools_webrtc/ios/tryserver.webrtc/ios_arm64_rel.json
index 7d2f923b57..08ae7e1983 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios_arm64_rel.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios_arm64_rel.json
@@ -2,7 +2,7 @@
   "comments": [
     "Builder for 64-bit devices."
   ],
-  "xcode build version": "9C40b",
+  "xcode build version": "10l232m",
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "dcheck_always_on=true",
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios_dbg.json b/tools_webrtc/ios/tryserver.webrtc/ios_dbg.json
index 4c5aca5ef7..e9d06c2a76 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios_dbg.json
@@ -2,7 +2,7 @@
   "comments": [
     "Builder for 32-bit devices."
   ],
-  "xcode build version": "9C40b",
+  "xcode build version": "10l232m",
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "ios_enable_code_signing=false",
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios_rel.json b/tools_webrtc/ios/tryserver.webrtc/ios_rel.json
index 81c16db60a..4521ef5153 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios_rel.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios_rel.json
@@ -2,7 +2,7 @@
   "comments": [
     "Builder for 32-bit devices."
   ],
-  "xcode build version": "9C40b",
+  "xcode build version": "10l232m",
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "dcheck_always_on=true",