diff --git a/src/GitVersionCore.Tests/ConfigProviderTests.cs b/src/GitVersionCore.Tests/ConfigProviderTests.cs
index c39740a69a..090561e920 100644
--- a/src/GitVersionCore.Tests/ConfigProviderTests.cs
+++ b/src/GitVersionCore.Tests/ConfigProviderTests.cs
@@ -77,6 +77,17 @@ public void OverwritesDefaultsWithProvidedConfig()
         config.Branches["develop"].Tag.ShouldBe("dev");
     }
 
+    [Test]
+    public void AllBranchesModeWhenUsingMainline()
+    {
+        var defaultConfig = ConfigurationProvider.Provide(repoPath, fileSystem);
+        const string text = @"mode: Mainline";
+        SetupConfigFileContent(text);
+        var config = ConfigurationProvider.Provide(repoPath, fileSystem);
+        var branches = config.Branches.Select(x => x.Value);
+        branches.All(branch => branch.VersioningMode == VersioningMode.Mainline).ShouldBe(true);
+    }
+
     [Test]
     public void CanRemoveTag()
     {
diff --git a/src/GitVersionCore/Configuration/ConfigurationProvider.cs b/src/GitVersionCore/Configuration/ConfigurationProvider.cs
index b72cd9ff3c..b4fc482c8e 100644
--- a/src/GitVersionCore/Configuration/ConfigurationProvider.cs
+++ b/src/GitVersionCore/Configuration/ConfigurationProvider.cs
@@ -109,7 +109,7 @@ public static void ApplyDefaultsTo(Config config)
                 new List<string>(),
                 defaultTag: "alpha",
                 defaultIncrementStrategy: IncrementStrategy.Minor,
-                defaultVersioningMode: VersioningMode.ContinuousDeployment,
+                defaultVersioningMode: config.VersioningMode == VersioningMode.Mainline? VersioningMode.Mainline : VersioningMode.ContinuousDeployment,
                 defaultTrackMergeTarget: true,
                 tracksReleaseBranches: true);
             ApplyBranchDefaults(config,