diff --git a/tools_webrtc/ios/client.webrtc/iOS32_Debug.json b/tools_webrtc/ios/client.webrtc/iOS32_Debug.json
index d2966ec3ad..b14809ff3d 100644
--- a/tools_webrtc/ios/client.webrtc/iOS32_Debug.json
+++ b/tools_webrtc/ios/client.webrtc/iOS32_Debug.json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Builder for 32-bit devices."
+    "Builder for 32-bit devices.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
diff --git a/tools_webrtc/ios/client.webrtc/iOS32_Release.json b/tools_webrtc/ios/client.webrtc/iOS32_Release.json
index e72a229178..97263256de 100644
--- a/tools_webrtc/ios/client.webrtc/iOS32_Release.json
+++ b/tools_webrtc/ios/client.webrtc/iOS32_Release.json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Builder for 32-bit devices."
+    "Builder for 32-bit devices.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
diff --git a/tools_webrtc/ios/client.webrtc/iOS32_Sim_Debug_(iOS_9.0).json b/tools_webrtc/ios/client.webrtc/iOS32_Sim_Debug_(iOS_9.0).json
index 7a56d46180..03b272bb53 100644
--- a/tools_webrtc/ios/client.webrtc/iOS32_Sim_Debug_(iOS_9.0).json
+++ b/tools_webrtc/ios/client.webrtc/iOS32_Sim_Debug_(iOS_9.0).json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Tests for 32-bit iOS simulators."
+    "Tests for 32-bit iOS simulators.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
diff --git a/tools_webrtc/ios/client.webrtc/iOS64_Debug.json b/tools_webrtc/ios/client.webrtc/iOS64_Debug.json
index 6532c90f50..f1fb7fa719 100644
--- a/tools_webrtc/ios/client.webrtc/iOS64_Debug.json
+++ b/tools_webrtc/ios/client.webrtc/iOS64_Debug.json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Builder for 64-bit devices."
+    "Builder for 64-bit devices.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
diff --git a/tools_webrtc/ios/client.webrtc/iOS64_Release.json b/tools_webrtc/ios/client.webrtc/iOS64_Release.json
index 8ca464c3c4..c2555c6a17 100644
--- a/tools_webrtc/ios/client.webrtc/iOS64_Release.json
+++ b/tools_webrtc/ios/client.webrtc/iOS64_Release.json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Builder for 64-bit devices."
+    "Builder for 64-bit devices.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
diff --git a/tools_webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_10.0).json b/tools_webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_10.0).json
index e759d95e36..d8a71f665a 100644
--- a/tools_webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_10.0).json
+++ b/tools_webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_10.0).json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Tests for 64-bit iOS simulators."
+    "Tests for 64-bit iOS simulators.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
diff --git a/tools_webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_11.0).json b/tools_webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_11.0).json
index 3dad91ba64..c303088b44 100644
--- a/tools_webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_11.0).json
+++ b/tools_webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_11.0).json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Tests for 64-bit iOS simulators."
+    "Tests for 64-bit iOS simulators.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
diff --git a/tools_webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_9.0).json b/tools_webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_9.0).json
index d27cdaa45f..bcf52d7283 100644
--- a/tools_webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_9.0).json
+++ b/tools_webrtc/ios/client.webrtc/iOS64_Sim_Debug_(iOS_9.0).json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Tests for 64-bit iOS simulators."
+    "Tests for 64-bit iOS simulators.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
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 29a113d413..1eacc9295f 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios32_sim_ios9_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios32_sim_ios9_dbg.json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Tests for 32-bit iOS simulators."
+    "Tests for 32-bit iOS simulators.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
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 6484ca1050..8cecf4a41e 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios10_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios10_dbg.json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Tests for 64-bit iOS simulators."
+    "Tests for 64-bit iOS simulators.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
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 b54f212acb..3a5f7c0cf6 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios11_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios11_dbg.json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Tests for 64-bit iOS simulators."
+    "Tests for 64-bit iOS simulators.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
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 fdfa7b382d..6c9848ee6d 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios9_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios9_dbg.json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Tests for 64-bit iOS simulators."
+    "Tests for 64-bit iOS simulators.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios_arm64_dbg.json b/tools_webrtc/ios/tryserver.webrtc/ios_arm64_dbg.json
index 7594cd2a36..43add6710e 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios_arm64_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios_arm64_dbg.json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Builder for 64-bit devices."
+    "Builder for 64-bit devices.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios_arm64_rel.json b/tools_webrtc/ios/tryserver.webrtc/ios_arm64_rel.json
index 08ae7e1983..95a57e5226 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios_arm64_rel.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios_arm64_rel.json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Builder for 64-bit devices."
+    "Builder for 64-bit devices.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios_dbg.json b/tools_webrtc/ios/tryserver.webrtc/ios_dbg.json
index e9d06c2a76..8be9e95c0f 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios_dbg.json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Builder for 32-bit devices."
+    "Builder for 32-bit devices.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios_rel.json b/tools_webrtc/ios/tryserver.webrtc/ios_rel.json
index 4521ef5153..f644940c7c 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios_rel.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios_rel.json
@@ -1,6 +1,7 @@
 {
   "comments": [
-    "Builder for 32-bit devices."
+    "Builder for 32-bit devices.",
+    "NOTE: Update cache entry in cr-buildbucket.cfg when changing xcode version."
   ],
   "xcode build version": "10l232m",
   "gn_args": [