diff --git a/src/Umbraco.Core/Migrations/MergeBuilder.cs b/src/Umbraco.Core/Migrations/MergeBuilder.cs
new file mode 100644
index 0000000000..f1eeea9dfa
--- /dev/null
+++ b/src/Umbraco.Core/Migrations/MergeBuilder.cs
@@ -0,0 +1,89 @@
+using System;
+using System.Collections.Generic;
+
+namespace Umbraco.Core.Migrations
+{
+    /// <summary>
+    /// Represents a migration plan builder for merges.
+    /// </summary>
+    public class MergeBuilder
+    {
+        private readonly MigrationPlan _plan;
+        private readonly List<Type> _migrations = new List<Type>();
+        private string _withLast;
+        private bool _with;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="MergeBuilder"/> class.
+        /// </summary>
+        internal MergeBuilder(MigrationPlan plan)
+        {
+            _plan = plan;
+        }
+
+        /// <summary>
+        /// Adds a transition to a target state through an empty migration.
+        /// </summary>
+        public MergeBuilder To(string targetState)
+            => To<NoopMigration>(targetState);
+
+        /// <summary>
+        /// Adds a transition to a target state through a migration.
+        /// </summary>
+        public MergeBuilder To<TMigration>(string targetState)
+            where TMigration : IMigration
+            => To(targetState, typeof(TMigration));
+
+        /// <summary>
+        /// Adds a transition to a target state through a migration.
+        /// </summary>
+        public MergeBuilder To(string targetState, Type migration)
+        {
+            if (_with)
+            {
+                _withLast = targetState;
+                targetState = _plan.CreateRandomState();
+            }
+            else
+            {
+                _migrations.Add(migration);
+            }
+
+            _plan.To(targetState, migration);
+            return this;
+        }
+
+        /// <summary>
+        /// Begins the second branch of the merge.
+        /// </summary>
+        public MergeBuilder With()
+        {
+            if (_with)
+                throw new InvalidOperationException("Cannot invoke With() twice.");
+            _with = true;
+            return this;
+        }
+
+        /// <summary>
+        /// Completes the merge.
+        /// </summary>
+        public MigrationPlan As(string targetState)
+        {
+            if (!_with)
+                throw new InvalidOperationException("Cannot invoke As() without invoking With() first.");
+
+            // reach final state
+            _plan.To(targetState);
+
+            // restart at former end of branch2
+            _plan.From(_withLast);
+            // and replay all branch1 migrations
+            foreach (var migration in _migrations)
+                _plan.To(_plan.CreateRandomState(), migration);
+            // reaching final state
+            _plan.To(targetState);
+
+            return _plan;
+        }
+    }
+}
diff --git a/src/Umbraco.Core/Migrations/MigrationPlan.cs b/src/Umbraco.Core/Migrations/MigrationPlan.cs
index 2e2bc8b661..85d9c1d2cc 100644
--- a/src/Umbraco.Core/Migrations/MigrationPlan.cs
+++ b/src/Umbraco.Core/Migrations/MigrationPlan.cs
@@ -72,8 +72,8 @@ namespace Umbraco.Core.Migrations
         }
 
         /// <summary>
-    /// Adds a transition to a target state through an empty migration.
-    /// </summary>
+        /// Adds a transition to a target state through an empty migration.
+        /// </summary>
         public MigrationPlan To(string targetState)
             => To<NoopMigration>(targetState);
 
@@ -100,9 +100,39 @@ namespace Umbraco.Core.Migrations
         }
 
         /// <summary>
-        /// Adds transitions to a target state by copying transitions from a start state to an end state.
+        /// Adds a transition to a target state through a migration, replacing a previous migration.
         /// </summary>
-        public MigrationPlan To(string targetState, string startState, string endState)
+        /// <typeparam name="TMigrationNew">The new migration.</typeparam>
+        /// <typeparam name="TMigrationRecover">The migration to use to recover from the previous target state.</typeparam>
+        /// <param name="recoverState">The previous target state, which we need to recover from through <typeparamref name="TMigrationRecover"/>.</param>
+        /// <param name="targetState">The new target state.</param>
+        public MigrationPlan ToWithReplace<TMigrationNew, TMigrationRecover>(string recoverState, string targetState)
+            where TMigrationNew: IMigration
+            where TMigrationRecover : IMigration
+        {
+            To<TMigrationNew>(targetState);
+            From(recoverState).To<TMigrationRecover>(targetState);
+            return this;
+        }
+
+        /// <summary>
+        /// Adds a transition to a target state through a migration, replacing a previous migration.
+        /// </summary>
+        /// <typeparam name="TMigrationNew">The new migration.</typeparam>
+        /// <param name="recoverState">The previous target state, which we can recover from directly.</param>
+        /// <param name="targetState">The new target state.</param>
+        public MigrationPlan ToWithReplace<TMigrationNew>(string recoverState, string targetState)
+            where TMigrationNew : IMigration
+        {
+            To<TMigrationNew>(targetState);
+            From(recoverState).To(targetState);
+            return this;
+        }
+
+        /// <summary>
+        /// Adds transitions to a target state by cloning transitions from a start state to an end state.
+        /// </summary>
+        public MigrationPlan ToWithClone(string startState, string endState, string targetState)
         {
             if (string.IsNullOrWhiteSpace(startState)) throw new ArgumentNullOrEmptyException(nameof(startState));
             if (string.IsNullOrWhiteSpace(endState)) throw new ArgumentNullOrEmptyException(nameof(endState));
@@ -128,7 +158,7 @@ namespace Umbraco.Core.Migrations
 
                 var newTargetState = transition.TargetState == endState
                     ? targetState
-                    : Guid.NewGuid().ToString("B").ToUpper();
+                    : CreateRandomState();
                 To(newTargetState, transition.MigrationType);
                 state = transition.TargetState;
             }
@@ -136,6 +166,17 @@ namespace Umbraco.Core.Migrations
             return this;
         }
 
+        /// <summary>
+        /// Creates a random, unique state.
+        /// </summary>
+        public virtual string CreateRandomState()
+            => Guid.NewGuid().ToString("B").ToUpper();
+
+        /// <summary>
+        /// Begins a merge.
+        /// </summary>
+        public MergeBuilder Merge() => new MergeBuilder(this);
+
         /// <summary>
         /// Gets the initial state.
         /// </summary>
@@ -257,13 +298,14 @@ namespace Umbraco.Core.Migrations
         /// Follows a path (for tests and debugging).
         /// </summary>
         /// <remarks>Does the same thing Execute does, but does not actually execute migrations.</remarks>
-        internal string FollowPath(string fromState, string toState = null)
+        internal IReadOnlyList<string> FollowPath(string fromState = null, string toState = null)
         {
             toState = toState.NullOrWhiteSpaceAsNull();
 
             Validate();
 
             var origState = fromState ?? string.Empty;
+            var states = new List<string> { origState };
 
             if (!_transitions.TryGetValue(origState, out var transition))
                 throw new Exception($"Unknown state \"{origState}\".");
@@ -272,6 +314,7 @@ namespace Umbraco.Core.Migrations
             {
                 var nextState = transition.TargetState;
                 origState = nextState;
+                states.Add(origState);
 
                 if (nextState == toState)
                 {
@@ -287,7 +330,7 @@ namespace Umbraco.Core.Migrations
             if (origState != (toState ?? _finalState))
                 throw new Exception($"Internal error, reached state {origState} which is not state {toState ?? _finalState}");
 
-            return origState;
+            return states;
         }
 
         /// <summary>
diff --git a/src/Umbraco.Core/Migrations/Upgrade/UmbracoPlan.cs b/src/Umbraco.Core/Migrations/Upgrade/UmbracoPlan.cs
index 4ef4df926c..f7e1ee9921 100644
--- a/src/Umbraco.Core/Migrations/Upgrade/UmbracoPlan.cs
+++ b/src/Umbraco.Core/Migrations/Upgrade/UmbracoPlan.cs
@@ -89,55 +89,27 @@ namespace Umbraco.Core.Migrations.Upgrade
             To<SuperZero>("{9DF05B77-11D1-475C-A00A-B656AF7E0908}");
             To<PropertyEditorsMigration>("{6FE3EF34-44A0-4992-B379-B40BC4EF1C4D}");
             To<LanguageColumns>("{7F59355A-0EC9-4438-8157-EB517E6D2727}");
-            //To<AddVariationTables1>("{941B2ABA-2D06-4E04-81F5-74224F1DB037}"); // AddVariationTables1 has been superseded by AddVariationTables2
-            To<AddVariationTables2>("{76DF5CD7-A884-41A5-8DC6-7860D95B1DF5}");
-
-            // way out of the commented state
-            From("{941B2ABA-2D06-4E04-81F5-74224F1DB037}");
-            To<AddVariationTables1A>("{76DF5CD7-A884-41A5-8DC6-7860D95B1DF5}");
-            // resume at {76DF5CD7-A884-41A5-8DC6-7860D95B1DF5} ...
-
+            ToWithReplace<AddVariationTables2, AddVariationTables1A>("{941B2ABA-2D06-4E04-81F5-74224F1DB037}", "{76DF5CD7-A884-41A5-8DC6-7860D95B1DF5}"); // kill AddVariationTable1
             To<RefactorMacroColumns>("{A7540C58-171D-462A-91C5-7A9AA5CB8BFD}");
-            To<UserForeignKeys>("{3E44F712-E2E3-473A-AE49-5D7F8E67CE3F}");  // shannon added that one - let's keep it as the default path
-            //To<AddTypedLabels>("{65D6B71C-BDD5-4A2E-8D35-8896325E9151}"); // stephan added that one = merge conflict, remove
-            To<AddTypedLabels>("{4CACE351-C6B9-4F0C-A6BA-85A02BBD39E4}");   // but add it after shannon's, with a new target state
 
-            // way out of the commented state
-            From("{65D6B71C-BDD5-4A2E-8D35-8896325E9151}");
-            To<UserForeignKeys>("{4CACE351-C6B9-4F0C-A6BA-85A02BBD39E4}");
-            // resume at {4CACE351-C6B9-4F0C-A6BA-85A02BBD39E4} ...
+            Merge().To<UserForeignKeys>("{3E44F712-E2E3-473A-AE49-5D7F8E67CE3F}") // shannon added that one
+            .With().To<AddTypedLabels>("{65D6B71C-BDD5-4A2E-8D35-8896325E9151}") // stephan added that one
+            .As("{4CACE351-C6B9-4F0C-A6BA-85A02BBD39E4}");
 
             To<ContentVariationMigration>("{1350617A-4930-4D61-852F-E3AA9E692173}");
             To<UpdateUmbracoConsent>("{39E5B1F7-A50B-437E-B768-1723AEC45B65}"); // from 7.12.0
-            //To<FallbackLanguage>("{CF51B39B-9B9A-4740-BB7C-EAF606A7BFBF}"); // andy added that one = merge conflict, remove
-            To<AddRelationTypeForMediaFolderOnDelete>("{0541A62B-EF87-4CA2-8225-F0EB98ECCC9F}"); // from 7.12.0
-            To<IncreaseLanguageIsoCodeColumnLength>("{EB34B5DC-BB87-4005-985E-D983EA496C38}"); // from 7.12.0
-            To<RenameTrueFalseField>("{517CE9EA-36D7-472A-BF4B-A0D6FB1B8F89}"); // from 7.12.0
-            To<SetDefaultTagsStorageType>("{BBD99901-1545-40E4-8A5A-D7A675C7D2F2}"); // from 7.12.0
-            //To<UpdateDefaultMandatoryLanguage>("{2C87AA47-D1BC-4ECB-8A73-2D8D1046C27F}"); // stephan added that one = merge conflict, remove
 
-            To<FallbackLanguage>("{8B14CEBD-EE47-4AAD-A841-93551D917F11}"); // add andy's after others, with a new target state
-
-            // way out of andy's
-            From("{CF51B39B-9B9A-4740-BB7C-EAF606A7BFBF}");
-            To("{8B14CEBD-EE47-4AAD-A841-93551D917F11}", "{39E5B1F7-A50B-437E-B768-1723AEC45B65}", "{BBD99901-1545-40E4-8A5A-D7A675C7D2F2}");
-            // resume at {8B14CEBD-EE47-4AAD-A841-93551D917F11} ...
-
-            To<UpdateDefaultMandatoryLanguage>("{5F4597F4-A4E0-4AFE-90B5-6D2F896830EB}"); // add stephan's after others, with a new target state
-
-            // way out of the commented state
-            From("{2C87AA47-D1BC-4ECB-8A73-2D8D1046C27F}");
-            To<FallbackLanguage>("{5F4597F4-A4E0-4AFE-90B5-6D2F896830EB}"); // to next
-            // resume at {5F4597F4-A4E0-4AFE-90B5-6D2F896830EB} ...
-
-            //To<RefactorVariantsModel>("{B19BF0F2-E1C6-4AEB-A146-BC559D97A2C6}");
-            To<RefactorVariantsModel>("{290C18EE-B3DE-4769-84F1-1F467F3F76DA}");
-
-            // way out of the commented state
-            From("{B19BF0F2-E1C6-4AEB-A146-BC559D97A2C6}");
-            To<FallbackLanguage>("{290C18EE-B3DE-4769-84F1-1F467F3F76DA}");
-            // resume at {290C18EE-B3DE-4769-84F1-1F467F3F76DA}...
+            Merge()
+                .To<AddRelationTypeForMediaFolderOnDelete>("{0541A62B-EF87-4CA2-8225-F0EB98ECCC9F}") // from 7.12.0
+                .To<IncreaseLanguageIsoCodeColumnLength>("{EB34B5DC-BB87-4005-985E-D983EA496C38}") // from 7.12.0
+                .To<RenameTrueFalseField>("{517CE9EA-36D7-472A-BF4B-A0D6FB1B8F89}") // from 7.12.0
+                .To<SetDefaultTagsStorageType>("{BBD99901-1545-40E4-8A5A-D7A675C7D2F2}") // from 7.12.0
+            .With()
+                .To<FallbackLanguage>("{CF51B39B-9B9A-4740-BB7C-EAF606A7BFBF}") // andy added that one
+            .As("{8B14CEBD-EE47-4AAD-A841-93551D917F11}");
 
+            ToWithReplace<UpdateDefaultMandatoryLanguage>("{2C87AA47-D1BC-4ECB-8A73-2D8D1046C27F}", "{5F4597F4-A4E0-4AFE-90B5-6D2F896830EB}"); // merge
+            ToWithReplace<RefactorVariantsModel>("{B19BF0F2-E1C6-4AEB-A146-BC559D97A2C6}", "{290C18EE-B3DE-4769-84F1-1F467F3F76DA}"); // merge
             To<DropTaskTables>("{6A2C7C1B-A9DB-4EA9-B6AB-78E7D5B722A7}");
             To<FixLockTablePrimaryKey>("{77874C77-93E5-4488-A404-A630907CEEF0}");
             To<AddLogTableColumns>("{8804D8E8-FE62-4E3A-B8A2-C047C2118C38}");
@@ -159,16 +131,22 @@ namespace Umbraco.Core.Migrations.Upgrade
             From("{init-7.10.2}").To("{init-7.10.0}"); // same as 7.10.0
             From("{init-7.10.3}").To("{init-7.10.0}"); // same as 7.10.0
             From("{init-7.10.4}").To("{init-7.10.0}"); // same as 7.10.0
+            From("{init-7.10.5}").To("{init-7.10.0}"); // same as 7.10.0
             From("{init-7.11.0}").To("{init-7.10.0}"); // same as 7.10.0
             From("{init-7.11.1}").To("{init-7.10.0}"); // same as 7.10.0
+            From("{init-7.11.2}").To("{init-7.10.0}"); // same as 7.10.0
 
             // 7.12.0 has migrations, define a custom chain which copies the chain
             // going from {init-7.10.0} to former final (1350617A) , and then goes straight to
             // main chain, skipping the migrations
             //
             From("{init-7.12.0}");
-            // target                                    copy from        copy to (former final)
-            To("{BBD99901-1545-40E4-8A5A-D7A675C7D2F2}", "{init-7.10.0}", "{1350617A-4930-4D61-852F-E3AA9E692173}");
+            //  start            stop                                      target
+            ToWithClone("{init-7.10.0}", "{1350617A-4930-4D61-852F-E3AA9E692173}", "{BBD99901-1545-40E4-8A5A-D7A675C7D2F2}");
+
+            From("{init-7.12.1}").To("{init-7.10.0}"); // same as 7.12.0
+            From("{init-7.12.2}").To("{init-7.10.0}"); // same as 7.12.0
+            From("{init-7.12.3}").To("{init-7.10.0}"); // same as 7.12.0
         }
     }
 }
diff --git a/src/Umbraco.Core/Umbraco.Core.csproj b/src/Umbraco.Core/Umbraco.Core.csproj
index ba0cf97bf7..8ef76ade37 100755
--- a/src/Umbraco.Core/Umbraco.Core.csproj
+++ b/src/Umbraco.Core/Umbraco.Core.csproj
@@ -339,6 +339,7 @@
     <Compile Include="Manifest\ManifestContentAppFactory.cs" />
     <Compile Include="Manifest\ManifestDashboardDefinition.cs" />
     <Compile Include="Migrations\IncompleteMigrationExpressionException.cs" />
+    <Compile Include="Migrations\MergeBuilder.cs" />
     <Compile Include="Migrations\MigrationBase_Extra.cs" />
     <Compile Include="Migrations\Upgrade\V_7_10_0\RenamePreviewFolder.cs" />
     <Compile Include="Migrations\Upgrade\V_7_12_0\AddRelationTypeForMediaFolderOnDelete.cs" />
diff --git a/src/Umbraco.Tests/Migrations/MigrationPlanTests.cs b/src/Umbraco.Tests/Migrations/MigrationPlanTests.cs
index 9aec42c252..add278f9eb 100644
--- a/src/Umbraco.Tests/Migrations/MigrationPlanTests.cs
+++ b/src/Umbraco.Tests/Migrations/MigrationPlanTests.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using Moq;
 using NPoco;
@@ -68,7 +69,6 @@ namespace Umbraco.Tests.Migrations
                 // save new state
                 kvs.SetValue("Umbraco.Tests.MigrationPlan", sourceState, state);
 
-                // fixme - what about post-migrations?
                 s.Complete();
             }
 
@@ -140,11 +140,11 @@ namespace Umbraco.Tests.Migrations
             var plan = new UmbracoPlan();
             plan.Validate();
             Console.WriteLine(plan.FinalState);
-            Assert.IsFalse(string.IsNullOrWhiteSpace(plan.FinalState));
+            Assert.IsFalse(plan.FinalState.IsNullOrWhiteSpace());
         }
 
         [Test]
-        public void CanCopyChain()
+        public void CanClone()
         {
             var plan = new MigrationPlan("default");
             plan
@@ -157,14 +157,46 @@ namespace Umbraco.Tests.Migrations
 
             plan
                 .From("xxx")
-                .To("yyy", "bbb", "ddd")
+                .ToWithClone("bbb", "ddd", "yyy")
                 .To("eee");
 
             WritePlanToConsole(plan);
 
             plan.Validate();
-            Assert.AreEqual("eee", plan.FollowPath("xxx"));
-            Assert.AreEqual("yyy", plan.FollowPath("xxx", "yyy"));
+            Assert.AreEqual("eee", plan.FollowPath("xxx").Last());
+            Assert.AreEqual("yyy", plan.FollowPath("xxx", "yyy").Last());
+        }
+
+        [Test]
+        public void CanMerge()
+        {
+            var plan = new MigrationPlan("default");
+            plan
+                .From(string.Empty)
+                .To("aaa")
+                .Merge()
+                    .To("bbb")
+                    .To("ccc")
+                .With()
+                    .To("ddd")
+                    .To("eee")
+                .As("fff")
+                .To("ggg");
+
+            WritePlanToConsole(plan);
+
+            plan.Validate();
+            AssertList(plan.FollowPath(), "", "aaa", "bbb", "ccc", "*", "*", "fff", "ggg");
+            AssertList(plan.FollowPath("ccc"), "ccc", "*", "*", "fff", "ggg");
+            AssertList(plan.FollowPath("eee"), "eee", "*", "*", "fff", "ggg");
+        }
+
+        private void AssertList(IReadOnlyList<string> states, params string[] expected)
+        {
+            Assert.AreEqual(expected.Length, states.Count, string.Join(", ", states));
+            for (var i = 0; i < expected.Length; i++)
+                if (expected[i] != "*")
+                    Assert.AreEqual(expected[i], states[i], "at:" + i);
         }
 
         private void WritePlanToConsole(MigrationPlan plan)