diff --git a/e2e/karma.conf.js b/e2e/karma.conf.js
index 3324cab2778..e478c88bf17 100644
--- a/e2e/karma.conf.js
+++ b/e2e/karma.conf.js
@@ -182,7 +182,7 @@ module.exports = function(config) {
         browser: 'safari',
         browser_version: 'latest',
         os: 'OS X',
-        os_version: 'High Sierra'
+        os_version: 'Mojave'
       },
       bs_ios_12: {
         base: 'BrowserStack',
diff --git a/e2e/script_tag_tests/tfjs-core-cpu/karma.conf.js b/e2e/script_tag_tests/tfjs-core-cpu/karma.conf.js
index 0b4e3ffbd91..55bc70140d8 100644
--- a/e2e/script_tag_tests/tfjs-core-cpu/karma.conf.js
+++ b/e2e/script_tag_tests/tfjs-core-cpu/karma.conf.js
@@ -95,13 +95,13 @@ module.exports = function(config) {
         browser: 'safari',
         browser_version: 'latest',
         os: 'OS X',
-        os_version: 'High Sierra'
+        os_version: 'Mojave'
       },
       bs_ios_12: {
         base: 'BrowserStack',
         device: 'iPhone X',
         os: 'iOS',
-        os_version: '11.0',
+        os_version: '12.3',
         real_mobile: true
       },
       bs_android_10: {
diff --git a/e2e/script_tag_tests/tfjs/karma.conf.js b/e2e/script_tag_tests/tfjs/karma.conf.js
index 5eaa9b78307..46146a61e25 100644
--- a/e2e/script_tag_tests/tfjs/karma.conf.js
+++ b/e2e/script_tag_tests/tfjs/karma.conf.js
@@ -87,13 +87,13 @@ module.exports = function(config) {
         browser: 'safari',
         browser_version: 'latest',
         os: 'OS X',
-        os_version: 'High Sierra'
+        os_version: 'Mojave'
       },
       bs_ios_12: {
         base: 'BrowserStack',
         device: 'iPhone X',
         os: 'iOS',
-        os_version: '11.0',
+        os_version: '12.3',
         real_mobile: true
       },
       bs_android_10: {
diff --git a/tools/karma_template.conf.js b/tools/karma_template.conf.js
index 9bf3a44d463..d6bc26ec529 100644
--- a/tools/karma_template.conf.js
+++ b/tools/karma_template.conf.js
@@ -53,7 +53,7 @@ const CUSTOM_LAUNCHERS = {
     browser: 'safari',
     browser_version: 'latest',
     os: 'OS X',
-    os_version: 'High Sierra'
+    os_version: 'Mojave'
   },
   bs_ios_12: {
     base: 'BrowserStack',
@@ -173,7 +173,8 @@ module.exports = function(config) {
       // This is necessary for non-flaky Safari tests. They usually pass just
       // fine without it, but sometimes, Safari will fail to connect to Karma.
       // If you want to remove this, prove that it's not flaky by running
-      // bazel test //tfjs-core/src:bs_safari_mac_from_pixels_worker_test --runs_per_test=100
+      // bazel test //tfjs-core/src:bs_safari_mac_from_pixels_worker_test
+      // --runs_per_test=100
       extraConfig.hostname = 'bs-local.com';
     }