diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index ee1258b4c1..e863a15ce5 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -96,10 +96,8 @@ then
     HOMEBREW_FORCE_BREWED_CURL="1"
   fi
 
-  # The system Git is too old for some GitHub's SSL ciphers on older
-  # macOS versions.
-  # https://github.com/blog/2507-weak-cryptographic-standards-removed
-  if [[ "$HOMEBREW_MACOS_VERSION_NUMERIC" -lt "100900" ]]
+  # The system Git is too old for some Homebrew functionality we rely on.
+  if [[ "$HOMEBREW_MACOS_VERSION_NUMERIC" -lt "101200" ]]
   then
     HOMEBREW_FORCE_BREWED_GIT="1"
   fi
diff --git a/Library/Homebrew/diagnostic.rb b/Library/Homebrew/diagnostic.rb
index 19223a1096..10a6c469eb 100644
--- a/Library/Homebrew/diagnostic.rb
+++ b/Library/Homebrew/diagnostic.rb
@@ -559,16 +559,16 @@ module Homebrew
       end
 
       def check_git_version
-        # https://help.github.com/articles/https-cloning-errors
+        # System Git version on macOS Sierra.
+        minimum_version = "2.14.3".freeze
         return unless Utils.git_available?
-        return unless Version.create(Utils.git_version) < Version.create("1.8.5")
+        return if Version.create(Utils.git_version) >= Version.create(minimum_version)
 
         git = Formula["git"]
         git_upgrade_cmd = git.any_version_installed? ? "upgrade" : "install"
         <<~EOS
           An outdated version (#{Utils.git_version}) of Git was detected in your PATH.
-          Git 1.8.5 or newer is required to perform checkouts over HTTPS from GitHub and
-          to support the 'git -C <path>' option.
+          Git #{minimum_version} or newer is required for Homebrew.
           Please upgrade:
             brew #{git_upgrade_cmd} git
         EOS