diff --git a/src/Umbraco.Core/Models/RelationItem.cs b/src/Umbraco.Core/Models/RelationItem.cs
index cebbc20951..f4e7e30aaf 100644
--- a/src/Umbraco.Core/Models/RelationItem.cs
+++ b/src/Umbraco.Core/Models/RelationItem.cs
@@ -14,7 +14,7 @@ namespace Umbraco.Cms.Core.Models
         public Guid NodeKey { get; set; }
 
         [DataMember(Name = "name")]
-        public string NodeName { get; set; }
+        public string? NodeName { get; set; }
 
         [DataMember(Name = "type")]
         public string NodeType { get; set; }
@@ -23,16 +23,16 @@ namespace Umbraco.Cms.Core.Models
         public Udi NodeUdi => Udi.Create(NodeType, NodeKey);
 
         [DataMember(Name = "icon")]
-        public string ContentTypeIcon { get; set; }
+        public string? ContentTypeIcon { get; set; }
 
         [DataMember(Name = "alias")]
-        public string ContentTypeAlias { get; set; }
+        public string? ContentTypeAlias { get; set; }
 
         [DataMember(Name = "contentTypeName")]
-        public string ContentTypeName { get; set; }
+        public string? ContentTypeName { get; set; }
 
         [DataMember(Name = "relationTypeName")]
-        public string RelationTypeName { get; set; }
+        public string? RelationTypeName { get; set; }
 
         [DataMember(Name = "relationTypeIsBidirectional")]
         public bool RelationTypeIsBidirectional { get; set; }
diff --git a/src/Umbraco.Core/UdiParser.cs b/src/Umbraco.Core/UdiParser.cs
index 427f8ce9f0..4a542e9352 100644
--- a/src/Umbraco.Core/UdiParser.cs
+++ b/src/Umbraco.Core/UdiParser.cs
@@ -74,8 +74,8 @@ namespace Umbraco.Cms.Core
         /// <param name="s">The string to convert.</param>
         /// <param name="udi">An Udi instance that contains the value that was parsed.</param>
         /// <returns>A boolean value indicating whether the string could be parsed.</returns>
-        public static bool TryParse<T>(string s, [MaybeNullWhen(returnValue: false)] out T udi)
-            where T : Udi
+        public static bool TryParse<T>(string? s, [MaybeNullWhen(returnValue: false)] out T udi)
+            where T : Udi?
         {
             var result = ParseInternal(s, true, false, out var parsed);
             if (result && parsed is T)
@@ -107,7 +107,7 @@ namespace Umbraco.Cms.Core
             return ParseInternal(s, true, knownTypes, out udi);
         }
 
-        private static bool ParseInternal(string s, bool tryParse, bool knownTypes,[MaybeNullWhen(returnValue: false)] out Udi udi)
+        private static bool ParseInternal(string? s, bool tryParse, bool knownTypes,[MaybeNullWhen(returnValue: false)] out Udi udi)
         {
             udi = null;
             if (Uri.IsWellFormedUriString(s, UriKind.Absolute) == false
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/AddTypedLabels.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/AddTypedLabels.cs
index 87d6edbc9f..69431867b1 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/AddTypedLabels.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/AddTypedLabels.cs
@@ -49,7 +49,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
             if (SqlSyntax.SupportsIdentityInsert())
                 Database.Execute(new Sql($"SET IDENTITY_INSERT {SqlSyntax.GetQuotedTableName(Cms.Core.Constants.DatabaseSchema.Tables.Node)} OFF "));
 
-            void InsertDataTypeDto(int id, string dbType, string configuration = null)
+            void InsertDataTypeDto(int id, string dbType, string? configuration = null)
             {
                 var dataTypeDto = new DataTypeDto
                 {
@@ -122,7 +122,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
         private class PropertyDataValue
         {
             public int Id { get; set; }
-            public string VarcharValue { get;set; }
+            public string? VarcharValue { get;set; }
         }
         // ReSharper restore UnusedAutoPropertyAccessor.Local
     }
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/ConvertRelatedLinksToMultiUrlPicker.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/ConvertRelatedLinksToMultiUrlPicker.cs
index 70f5b6f0bf..a6ff99f2c7 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/ConvertRelatedLinksToMultiUrlPicker.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/ConvertRelatedLinksToMultiUrlPicker.cs
@@ -60,9 +60,14 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
 
                 var relatedLinks = JsonConvert.DeserializeObject<List<RelatedLink>>(value);
                 var links = new List<LinkDto>();
+                if (relatedLinks is null)
+                {
+                    return;
+                }
+
                 foreach (var relatedLink in relatedLinks)
                 {
-                    GuidUdi udi = null;
+                    GuidUdi? udi = null;
                     if (relatedLink.IsInternal)
                     {
                         var linkIsUdi = UdiParser.TryParse(relatedLink.Link, out udi);
@@ -114,9 +119,9 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
         public int? Id { get; internal set; }
         internal bool IsDeleted { get; set; }
         [JsonProperty("caption")]
-        public string Caption { get; set; }
+        public string? Caption { get; set; }
         [JsonProperty("link")]
-        public string Link { get; set; }
+        public string? Link { get; set; }
         [JsonProperty("newWindow")]
         public bool NewWindow { get; set; }
         [JsonProperty("isInternal")]
@@ -127,15 +132,15 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
     internal class LinkDto
     {
         [DataMember(Name = "name")]
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         [DataMember(Name = "target")]
-        public string Target { get; set; }
+        public string? Target { get; set; }
 
         [DataMember(Name = "udi")]
-        public GuidUdi Udi { get; set; }
+        public GuidUdi? Udi { get; set; }
 
         [DataMember(Name = "url")]
-        public string Url { get; set; }
+        public string? Url { get; set; }
     }
 }
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/ContentPickerPreValueMigrator.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/ContentPickerPreValueMigrator.cs
index 231c59b315..7e1711604a 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/ContentPickerPreValueMigrator.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/ContentPickerPreValueMigrator.cs
@@ -5,10 +5,10 @@
         public override bool CanMigrate(string editorAlias)
             => editorAlias == Cms.Core.Constants.PropertyEditors.Legacy.Aliases.ContentPicker2;
 
-        public override string GetNewAlias(string editorAlias)
+        public override string? GetNewAlias(string editorAlias)
             => null;
 
-        protected override object GetPreValueValue(PreValueDto preValue)
+        protected override object? GetPreValueValue(PreValueDto preValue)
         {
             if (preValue.Alias == "showOpenButton" ||
                 preValue.Alias == "ignoreUserStartNodes")
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/DecimalPreValueMigrator.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/DecimalPreValueMigrator.cs
index e5a331cfbe..0383e7029e 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/DecimalPreValueMigrator.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/DecimalPreValueMigrator.cs
@@ -8,14 +8,14 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.DataTypes
         public override bool CanMigrate(string editorAlias)
             => editorAlias == "Umbraco.Decimal";
 
-        protected override object GetPreValueValue(PreValueDto preValue)
+        protected override object? GetPreValueValue(PreValueDto preValue)
         {
             if (preValue.Alias == "min" ||
                 preValue.Alias == "step" ||
                 preValue.Alias == "max")
                 return decimal.TryParse(preValue.Value, out var d) ? (decimal?) d : null;
 
-            return preValue.Value.DetectIsJson() ? JsonConvert.DeserializeObject(preValue.Value) : preValue.Value;
+            return preValue.Value?.DetectIsJson() ?? false ? JsonConvert.DeserializeObject(preValue.Value) : preValue.Value;
         }
     }
 }
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/DefaultPreValueMigrator.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/DefaultPreValueMigrator.cs
index 0d3b25259c..30507ac3ec 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/DefaultPreValueMigrator.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/DefaultPreValueMigrator.cs
@@ -11,7 +11,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.DataTypes
         public virtual bool CanMigrate(string editorAlias)
             => true;
 
-        public virtual string GetNewAlias(string editorAlias)
+        public virtual string? GetNewAlias(string editorAlias)
             => editorAlias;
 
         public object GetConfiguration(int dataTypeId, string editorAlias, Dictionary<string, PreValueDto> preValues)
@@ -35,9 +35,9 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.DataTypes
         protected virtual IEnumerable<PreValueDto> GetPreValues(IEnumerable<PreValueDto> preValues)
             => preValues;
 
-        protected virtual object GetPreValueValue(PreValueDto preValue)
+        protected virtual object? GetPreValueValue(PreValueDto preValue)
         {
-            return preValue.Value.DetectIsJson() ? JsonConvert.DeserializeObject(preValue.Value) : preValue.Value;
+            return preValue.Value?.DetectIsJson() ?? false ? JsonConvert.DeserializeObject(preValue.Value) : preValue.Value;
         }
     }
 }
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/DropDownFlexiblePreValueMigrator.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/DropDownFlexiblePreValueMigrator.cs
index fe55844c95..6c0f3d4869 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/DropDownFlexiblePreValueMigrator.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/DropDownFlexiblePreValueMigrator.cs
@@ -8,7 +8,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.DataTypes
         public bool CanMigrate(string editorAlias)
             => editorAlias == "Umbraco.DropDown.Flexible";
 
-        public virtual string GetNewAlias(string editorAlias)
+        public virtual string? GetNewAlias(string editorAlias)
             => null;
 
         public object GetConfiguration(int dataTypeId, string editorAlias, Dictionary<string, PreValueDto> preValues)
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/IPreValueMigrator.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/IPreValueMigrator.cs
index c6ed38ae16..5489fd626e 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/IPreValueMigrator.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/IPreValueMigrator.cs
@@ -23,7 +23,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.DataTypes
         /// when for instance we know it will fail, and another, later migration will
         /// deal with it.</para>
         /// </remarks>
-        string GetNewAlias(string editorAlias);
+        string? GetNewAlias(string editorAlias);
 
         /// <summary>
         /// Gets the configuration object corresponding to preValue.
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/ListViewPreValueMigrator.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/ListViewPreValueMigrator.cs
index 0b9bb4519c..c306e3eef3 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/ListViewPreValueMigrator.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/ListViewPreValueMigrator.cs
@@ -16,12 +16,14 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.DataTypes
             return preValues.Where(preValue => preValue.Alias != "displayAtTabNumber");
         }
 
-        protected override object GetPreValueValue(PreValueDto preValue)
+        protected override object? GetPreValueValue(PreValueDto preValue)
         {
             if (preValue.Alias == "pageSize")
+            {
                 return int.TryParse(preValue.Value, NumberStyles.Integer, CultureInfo.InvariantCulture, out var i) ? (int?)i : null;
+            }
 
-            return preValue.Value.DetectIsJson() ? JsonConvert.DeserializeObject(preValue.Value) : preValue.Value;
+            return preValue.Value?.DetectIsJson() ?? false ? JsonConvert.DeserializeObject(preValue.Value) : preValue.Value;
         }
     }
 }
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/MarkdownEditorPreValueMigrator.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/MarkdownEditorPreValueMigrator.cs
index 1c0004506a..9f8e7da57a 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/MarkdownEditorPreValueMigrator.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/MarkdownEditorPreValueMigrator.cs
@@ -5,7 +5,7 @@
         public override bool CanMigrate(string editorAlias)
             => editorAlias == Cms.Core.Constants.PropertyEditors.Aliases.MarkdownEditor;
 
-        protected override object GetPreValueValue(PreValueDto preValue)
+        protected override object? GetPreValueValue(PreValueDto preValue)
         {
             if (preValue.Alias == "preview")
                 return preValue.Value == "1";
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/MediaPickerPreValueMigrator.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/MediaPickerPreValueMigrator.cs
index 39b67984c8..364cc3e86b 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/MediaPickerPreValueMigrator.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/MediaPickerPreValueMigrator.cs
@@ -24,7 +24,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.DataTypes
         }
         */
 
-        protected override object GetPreValueValue(PreValueDto preValue)
+        protected override object? GetPreValueValue(PreValueDto preValue)
         {
             if (preValue.Alias == "multiPicker" ||
                 preValue.Alias == "onlyImages" ||
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/NestedContentPreValueMigrator.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/NestedContentPreValueMigrator.cs
index 98eac62f15..761f55be4e 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/NestedContentPreValueMigrator.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/NestedContentPreValueMigrator.cs
@@ -17,7 +17,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.DataTypes
         }
         */
 
-        protected override object GetPreValueValue(PreValueDto preValue)
+        protected override object? GetPreValueValue(PreValueDto preValue)
         {
             if (preValue.Alias == "confirmDeletes" ||
                 preValue.Alias == "showIcons" ||
@@ -28,7 +28,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.DataTypes
                 preValue.Alias == "maxItems")
                 return int.TryParse(preValue.Value, NumberStyles.Integer, CultureInfo.InvariantCulture, out var i) ? (int?)i : null;
 
-            return preValue.Value.DetectIsJson() ? JsonConvert.DeserializeObject(preValue.Value) : preValue.Value;
+            return preValue.Value?.DetectIsJson() ?? false ? JsonConvert.DeserializeObject(preValue.Value) : preValue.Value;
         }
     }
 }
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/PreValueDto.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/PreValueDto.cs
index 0531d571f3..d3f4b06737 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/PreValueDto.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/PreValueDto.cs
@@ -13,12 +13,12 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.DataTypes
         public int NodeId { get; set; }
 
         [Column("alias")]
-        public string Alias { get; set; }
+        public string Alias { get; set; } = null!;
 
         [Column("sortorder")]
         public int SortOrder { get; set; }
 
         [Column("value")]
-        public string Value { get; set; }
+        public string? Value { get; set; }
     }
 }
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/PreValueMigratorCollection.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/PreValueMigratorCollection.cs
index ca4ec9bfe1..b304098188 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/PreValueMigratorCollection.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/PreValueMigratorCollection.cs
@@ -17,7 +17,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.DataTypes
             _logger = logger;
         }
 
-        public IPreValueMigrator GetMigrator(string editorAlias)
+        public IPreValueMigrator? GetMigrator(string editorAlias)
         {
             var migrator = this.FirstOrDefault(x => x.CanMigrate(editorAlias));
             _logger.LogDebug("Getting migrator for \"{EditorAlias}\" = {MigratorType}", editorAlias, migrator == null ? "<null>" : migrator.GetType().Name);
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/RichTextPreValueMigrator.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/RichTextPreValueMigrator.cs
index 1f704e0b3d..0abcd86a96 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/RichTextPreValueMigrator.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/RichTextPreValueMigrator.cs
@@ -11,12 +11,12 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.DataTypes
         public override string GetNewAlias(string editorAlias)
             => Cms.Core.Constants.PropertyEditors.Aliases.TinyMce;
 
-        protected override object GetPreValueValue(PreValueDto preValue)
+        protected override object? GetPreValueValue(PreValueDto preValue)
         {
             if (preValue.Alias == "hideLabel")
                 return preValue.Value == "1";
 
-            return preValue.Value.DetectIsJson() ? JsonConvert.DeserializeObject(preValue.Value) : preValue.Value;
+            return preValue.Value?.DetectIsJson() ?? false ? JsonConvert.DeserializeObject(preValue.Value) : preValue.Value;
         }
     }
 }
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/ValueListPreValueMigrator.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/ValueListPreValueMigrator.cs
index be6b270048..44b12addd2 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/ValueListPreValueMigrator.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DataTypes/ValueListPreValueMigrator.cs
@@ -19,7 +19,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.DataTypes
         public bool CanMigrate(string editorAlias)
             => _editors.Contains(editorAlias);
 
-        public virtual string GetNewAlias(string editorAlias)
+        public virtual string? GetNewAlias(string editorAlias)
             => null;
 
         public object GetConfiguration(int dataTypeId, string editorAlias, Dictionary<string, PreValueDto> preValues)
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DropDownPropertyEditorsMigration.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DropDownPropertyEditorsMigration.cs
index a03c87159b..b4f6b5cf9d 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DropDownPropertyEditorsMigration.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/DropDownPropertyEditorsMigration.cs
@@ -37,7 +37,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
         private bool Migrate(IEnumerable<DataTypeDto> dataTypes)
         {
             var refreshCache = false;
-            ConfigurationEditor configurationEditor = null;
+            ConfigurationEditor? configurationEditor = null;
 
             foreach (var dataType in dataTypes)
             {
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/Models/ContentTypeDto80.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/Models/ContentTypeDto80.cs
index 9328e774e1..bbd1646ad5 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/Models/ContentTypeDto80.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/Models/ContentTypeDto80.cs
@@ -29,21 +29,21 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.Models
 
         [Column("alias")]
         [NullSetting(NullSetting = NullSettings.Null)]
-        public string Alias { get; set; }
+        public string? Alias { get; set; }
 
         [Column("icon")]
         [Index(IndexTypes.NonClustered)]
         [NullSetting(NullSetting = NullSettings.Null)]
-        public string Icon { get; set; }
+        public string? Icon { get; set; }
 
         [Column("thumbnail")]
         [Constraint(Default = "folder.png")]
-        public string Thumbnail { get; set; }
+        public string? Thumbnail { get; set; }
 
         [Column("description")]
         [NullSetting(NullSetting = NullSettings.Null)]
         [Length(1500)]
-        public string Description { get; set; }
+        public string? Description { get; set; }
 
         [Column("isContainer")]
         [Constraint(Default = "0")]
@@ -58,6 +58,6 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.Models
         public byte Variations { get; set; }
 
         [ResultColumn]
-        public NodeDto NodeDto { get; set; }
+        public NodeDto? NodeDto { get; set; }
     }
 }
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/Models/PropertyDataDto80.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/Models/PropertyDataDto80.cs
index 69aabd4e21..1e9e93aa53 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/Models/PropertyDataDto80.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/Models/PropertyDataDto80.cs
@@ -48,7 +48,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.Models
         [Index(IndexTypes.NonClustered, Name = "IX_" + TableName + "_Segment")]
         [NullSetting(NullSetting = NullSettings.Null)]
         [Length(SegmentLength)]
-        public string Segment { get; set; }
+        public string? Segment { get; set; }
 
         [Column("intValue")]
         [NullSetting(NullSetting = NullSettings.Null)]
@@ -69,19 +69,19 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.Models
         [Column("varcharValue")]
         [NullSetting(NullSetting = NullSettings.Null)]
         [Length(VarcharLength)]
-        public string VarcharValue { get; set; }
+        public string? VarcharValue { get; set; }
 
         [Column("textValue")]
         [NullSetting(NullSetting = NullSettings.Null)]
         [SpecialDbType(SpecialDbTypes.NTEXT)]
-        public string TextValue { get; set; }
+        public string? TextValue { get; set; }
 
         [ResultColumn]
         [Reference(ReferenceType.OneToOne, ColumnName = "PropertyTypeId")]
-        public PropertyTypeDto80 PropertyTypeDto { get; set; }
+        public PropertyTypeDto80? PropertyTypeDto { get; set; }
 
         [Ignore]
-        public object Value
+        public object? Value
         {
             get
             {
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/Models/PropertyTypeDto80.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/Models/PropertyTypeDto80.cs
index 485be0d3b0..4d61521d00 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/Models/PropertyTypeDto80.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/Models/PropertyTypeDto80.cs
@@ -36,11 +36,11 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.Models
 
         [Index(IndexTypes.NonClustered, Name = "IX_cmsPropertyTypeAlias")]
         [Column("Alias")]
-        public string Alias { get; set; }
+        public string Alias { get; set; } = null!;
 
         [Column("Name")]
         [NullSetting(NullSetting = NullSettings.Null)]
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         [Column("sortOrder")]
         [Constraint(Default = "0")]
@@ -52,12 +52,12 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.Models
 
         [Column("validationRegExp")]
         [NullSetting(NullSetting = NullSettings.Null)]
-        public string ValidationRegExp { get; set; }
+        public string? ValidationRegExp { get; set; }
 
         [Column("Description")]
         [NullSetting(NullSetting = NullSettings.Null)]
         [Length(2000)]
-        public string Description { get; set; }
+        public string? Description { get; set; }
 
         [Column("variations")]
         [Constraint(Default = "1" /*ContentVariation.InvariantNeutral*/)]
@@ -65,7 +65,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0.Models
 
         [ResultColumn]
         [Reference(ReferenceType.OneToOne, ColumnName = "DataTypeId")]
-        public DataTypeDto DataTypeDto { get; set; }
+        public DataTypeDto? DataTypeDto { get; set; }
 
         [Column("UniqueID")]
         [NullSetting(NullSetting = NullSettings.NotNull)]
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/PropertyEditorsMigrationBase.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/PropertyEditorsMigrationBase.cs
index f24cfc1142..92f2e7d4b5 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/PropertyEditorsMigrationBase.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/PropertyEditorsMigrationBase.cs
@@ -31,17 +31,17 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
             return Database.Fetch<DataTypeDto>(sql);
         }
 
-        protected int[] ConvertStringValues(string val)
+        protected int[]? ConvertStringValues(string? val)
         {
-            var splitVals = val.Split(Constants.CharArrays.Comma, StringSplitOptions.RemoveEmptyEntries);
+            var splitVals = val?.Split(Constants.CharArrays.Comma, StringSplitOptions.RemoveEmptyEntries);
 
-            var intVals = splitVals
+            var intVals = splitVals?
                 .Select(x => int.TryParse(x, NumberStyles.Integer, CultureInfo.InvariantCulture, out var i) ? i : int.MinValue)
                 .Where(x => x != int.MinValue)
                 .ToArray();
 
             //only return if the number of values are the same (i.e. All INTs)
-            if (splitVals.Length == intVals.Length)
+            if (splitVals?.Length == intVals?.Length)
                 return intVals;
 
             return null;
@@ -50,7 +50,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
         internal bool UpdatePropertyDataDto(PropertyDataDto propData, ValueListConfiguration config, bool isMultiple)
         {
             //Get the INT ids stored for this property/drop down
-            int[] ids = null;
+            int[]? ids = null;
             if (!propData.VarcharValue.IsNullOrWhiteSpace())
             {
                 ids = ConvertStringValues(propData.VarcharValue);
@@ -74,7 +74,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
             foreach (var id in ids)
             {
                 var val = config.Items.FirstOrDefault(x => x.Id == id);
-                if (val != null)
+                if (val?.Value != null)
                 {
                     values.Add(val.Value);
                     continue;
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/RadioAndCheckboxPropertyEditorsMigration.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/RadioAndCheckboxPropertyEditorsMigration.cs
index 1dc0b7f2c3..f462510a2a 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/RadioAndCheckboxPropertyEditorsMigration.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/RadioAndCheckboxPropertyEditorsMigration.cs
@@ -43,7 +43,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
         private bool Migrate(IEnumerable<DataTypeDto> dataTypes, bool isMultiple)
         {
             var refreshCache = false;
-            ConfigurationEditor configurationEditor = null;
+            ConfigurationEditor? configurationEditor = null;
 
             foreach (var dataType in dataTypes)
             {
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/RefactorVariantsModel.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/RefactorVariantsModel.cs
index a7759e557c..1ff19e0698 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/RefactorVariantsModel.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/RefactorVariantsModel.cs
@@ -73,7 +73,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
         {
             public int NodeId { get; set; }
             public int LanguageId { get; set; }
-            public string Name { get; set; }
+            public string? Name { get; set; }
         }
         // ReSharper restore UnusedAutoPropertyAccessor.Local
     }
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/UpdatePickerIntegerValuesToUdi.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/UpdatePickerIntegerValuesToUdi.cs
index 3cbc7357e5..7fe50b2159 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/UpdatePickerIntegerValuesToUdi.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_0_0/UpdatePickerIntegerValuesToUdi.cs
@@ -32,8 +32,8 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
                     case Cms.Core.Constants.PropertyEditors.Aliases.ContentPicker:
                     case Cms.Core.Constants.PropertyEditors.Aliases.MediaPicker:
                         {
-                            var config = JsonConvert.DeserializeObject<JObject>(datatype.Configuration);
-                            var startNodeId = config.Value<string>("startNodeId");
+                            var config = JsonConvert.DeserializeObject<JObject>(datatype.Configuration!);
+                            var startNodeId = config!.Value<string>("startNodeId");
                             if (!startNodeId.IsNullOrWhiteSpace() && int.TryParse(startNodeId, NumberStyles.Integer, CultureInfo.InvariantCulture, out var intStartNode))
                             {
                                 var guid = intStartNode <= 0
@@ -45,10 +45,10 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
                                     var udi = new GuidUdi(datatype.EditorAlias == Cms.Core.Constants.PropertyEditors.Aliases.MediaPicker
                                         ? Cms.Core.Constants.UdiEntityType.Media
                                         : Cms.Core.Constants.UdiEntityType.Document, guid.Value);
-                                    config["startNodeId"] = new JValue(udi.ToString());
+                                    config!["startNodeId"] = new JValue(udi.ToString());
                                 }
                                 else
-                                    config.Remove("startNodeId");
+                                    config!.Remove("startNodeId");
 
                                 datatype.Configuration = JsonConvert.SerializeObject(config);
                                 Database.Update(datatype);
@@ -58,8 +58,8 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
                         }
                     case Cms.Core.Constants.PropertyEditors.Aliases.MultiNodeTreePicker:
                         {
-                            var config = JsonConvert.DeserializeObject<JObject>(datatype.Configuration);
-                            var startNodeConfig = config.Value<JObject>("startNode");
+                            var config = JsonConvert.DeserializeObject<JObject>(datatype.Configuration!);
+                            var startNodeConfig = config!.Value<JObject>("startNode");
                             if (startNodeConfig != null)
                             {
                                 var startNodeId = startNodeConfig.Value<string>("id");
@@ -73,8 +73,8 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_0_0
                                         : Context.Database.ExecuteScalar<Guid?>(
                                             Sql().Select<NodeDto>(x => x.UniqueId).From<NodeDto>().Where<NodeDto>(x => x.NodeId == intStartNode));
 
-                                    string entityType = null;
-                                    switch (objectType.ToLowerInvariant())
+                                    string? entityType = null;
+                                    switch (objectType?.ToLowerInvariant())
                                     {
                                         case "content":
                                             entityType = Cms.Core.Constants.UdiEntityType.Document;
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_15_0/AddCmsContentNuByteColumn.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_15_0/AddCmsContentNuByteColumn.cs
index 10db1964e0..23bb979dd9 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_15_0/AddCmsContentNuByteColumn.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_15_0/AddCmsContentNuByteColumn.cs
@@ -38,7 +38,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_15_0
             [Column("data")]
             [SpecialDbType(SpecialDbTypes.NTEXT)]
             [NullSetting(NullSetting = NullSettings.Null)]
-            public string Data { get; set; }
+            public string? Data { get; set; }
 
             [Column("rv")]
             public long Rv { get; set; }
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_17_0/AddPropertyTypeGroupColumns.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_17_0/AddPropertyTypeGroupColumns.cs
index 9230987389..feedc56d9a 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_17_0/AddPropertyTypeGroupColumns.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_17_0/AddPropertyTypeGroupColumns.cs
@@ -33,7 +33,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_17_0
 
         internal IEnumerable<PropertyTypeGroupDto> PopulateAliases(IEnumerable<PropertyTypeGroupDto> dtos)
         {
-            foreach (var dtosPerAlias in dtos.GroupBy(x => x.Text.ToSafeAlias(_shortStringHelper, true)))
+            foreach (var dtosPerAlias in dtos.GroupBy(x => x.Text?.ToSafeAlias(_shortStringHelper, true)))
             {
                 var dtosPerAliasAndText = dtosPerAlias.GroupBy(x => x.Text);
                 var numberSuffix = 1;
@@ -41,7 +41,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_17_0
                 {
                     foreach (var dto in dtosPerText)
                     {
-                        dto.Alias = dtosPerAlias.Key;
+                        dto.Alias = dtosPerAlias.Key ?? string.Empty;
 
                         if (numberSuffix > 1)
                         {
diff --git a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_1_0/ConvertTinyMceAndGridMediaUrlsToLocalLink.cs b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_1_0/ConvertTinyMceAndGridMediaUrlsToLocalLink.cs
index e0f2fb3831..96d60a30e5 100644
--- a/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_1_0/ConvertTinyMceAndGridMediaUrlsToLocalLink.cs
+++ b/src/Umbraco.Infrastructure/Migrations/Upgrade/V_8_1_0/ConvertTinyMceAndGridMediaUrlsToLocalLink.cs
@@ -28,7 +28,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_1_0
                 RegexOptions.Compiled | RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace);
 
             var sqlPropertyData = Sql()
-                .Select<PropertyDataDto80>(r => r.Select(x => x.PropertyTypeDto, r1 => r1.Select(x => x.DataTypeDto)))
+                .Select<PropertyDataDto80>(r => r.Select(x => x.PropertyTypeDto, r1 => r1.Select(x => x!.DataTypeDto)))
                 .From<PropertyDataDto80>()
                     .InnerJoin<PropertyTypeDto80>().On<PropertyDataDto80, PropertyTypeDto80>((left, right) => left.PropertyTypeId == right.Id)
                     .InnerJoin<DataTypeDto>().On<PropertyTypeDto80, DataTypeDto>((left, right) => left.DataTypeId == right.NodeId)
@@ -46,7 +46,7 @@ namespace Umbraco.Cms.Infrastructure.Migrations.Upgrade.V_8_1_0
 
 
                 bool propertyChanged = false;
-                if (property.PropertyTypeDto.DataTypeDto.EditorAlias == Cms.Core.Constants.PropertyEditors.Aliases.Grid)
+                if (property.PropertyTypeDto?.DataTypeDto?.EditorAlias == Cms.Core.Constants.PropertyEditors.Aliases.Grid)
                 {
                     try
                     {
diff --git a/src/Umbraco.Infrastructure/Persistence/ScalarMapper.cs b/src/Umbraco.Infrastructure/Persistence/ScalarMapper.cs
index 9b6eada924..827aef1932 100644
--- a/src/Umbraco.Infrastructure/Persistence/ScalarMapper.cs
+++ b/src/Umbraco.Infrastructure/Persistence/ScalarMapper.cs
@@ -10,5 +10,5 @@ public abstract class ScalarMapper<T> : IScalarMapper
     protected abstract T Map(object value);
 
     /// <inheritdoc />
-    object IScalarMapper.Map(object value) => Map(value);
+    object IScalarMapper.Map(object value) => Map(value)!;
 }
diff --git a/src/Umbraco.Infrastructure/Routing/RedirectTrackingHandler.cs b/src/Umbraco.Infrastructure/Routing/RedirectTrackingHandler.cs
index 4b34cf41a9..dabee6db9d 100644
--- a/src/Umbraco.Infrastructure/Routing/RedirectTrackingHandler.cs
+++ b/src/Umbraco.Infrastructure/Routing/RedirectTrackingHandler.cs
@@ -100,7 +100,7 @@ namespace Umbraco.Cms.Core.Routing
                 return;
             }
 
-            IPublishedContentCache contentCache = publishedSnapshot?.Content;
+            IPublishedContentCache? contentCache = publishedSnapshot?.Content;
             IPublishedContent? entityContent = contentCache?.GetById(entity.Id);
             if (entityContent is null)
             {
diff --git a/src/Umbraco.Infrastructure/Scoping/Scope.cs b/src/Umbraco.Infrastructure/Scoping/Scope.cs
index 008556225b..59d6f83022 100644
--- a/src/Umbraco.Infrastructure/Scoping/Scope.cs
+++ b/src/Umbraco.Infrastructure/Scoping/Scope.cs
@@ -53,7 +53,7 @@ namespace Umbraco.Cms.Core.Scoping
         private Dictionary<Guid, Dictionary<int, int>>? _readLocksDictionary;
         private HashSet<int>? _writeLocks;
         private Dictionary<Guid, Dictionary<int, int>>? _writeLocksDictionary;
-        private Queue<IDistributedLock> _acquiredLocks;
+        private Queue<IDistributedLock>? _acquiredLocks;
 
         // initializes a new scope
         private Scope(
@@ -450,7 +450,7 @@ namespace Umbraco.Cms.Core.Scoping
             {
                 while (!_acquiredLocks?.IsCollectionEmpty() ?? false)
                 {
-                    _acquiredLocks.Dequeue().Dispose();
+                    _acquiredLocks?.Dequeue().Dispose();
                 }
 
                 // We're the parent scope, make sure that locks of all scopes has been cleared
@@ -1104,7 +1104,7 @@ namespace Umbraco.Cms.Core.Scoping
             {
                 // Something went wrong and we didn't get the lock
                 // Since we at this point have determined that we haven't got any lock with an ID of LockID, it's safe to completely remove it instead of decrementing.
-                locks[instanceId].Remove(lockId);
+                locks?[instanceId].Remove(lockId);
 
                 // It needs to be removed from the HashSet as well, because that's how we determine to acquire a lock.
                 locksSet.Remove(lockId);
@@ -1118,7 +1118,7 @@ namespace Umbraco.Cms.Core.Scoping
         /// <param name="lockId">Lock object identifier to lock.</param>
         /// <param name="timeout">TimeSpan specifying the timout period.</param>
         private void ObtainReadLock(int lockId, TimeSpan? timeout)
-            => _acquiredLocks.Enqueue(_scopeProvider.DistributedLockingMechanismFactory.DistributedLockingMechanism.ReadLock(lockId, timeout));
+            => _acquiredLocks?.Enqueue(_scopeProvider.DistributedLockingMechanismFactory.DistributedLockingMechanism!.ReadLock(lockId, timeout));
 
         /// <summary>
         ///     Obtains a write lock with a custom timeout.
@@ -1126,6 +1126,6 @@ namespace Umbraco.Cms.Core.Scoping
         /// <param name="lockId">Lock object identifier to lock.</param>
         /// <param name="timeout">TimeSpan specifying the timout period.</param>
         private void ObtainWriteLock(int lockId, TimeSpan? timeout)
-            => _acquiredLocks.Enqueue(_scopeProvider.DistributedLockingMechanismFactory.DistributedLockingMechanism.WriteLock(lockId, timeout));
+            => _acquiredLocks?.Enqueue(_scopeProvider.DistributedLockingMechanismFactory.DistributedLockingMechanism!.WriteLock(lockId, timeout));
     }
 }
diff --git a/src/Umbraco.Infrastructure/Security/MemberUserStore.cs b/src/Umbraco.Infrastructure/Security/MemberUserStore.cs
index 1b660ebf4e..e8d93d9221 100644
--- a/src/Umbraco.Infrastructure/Security/MemberUserStore.cs
+++ b/src/Umbraco.Infrastructure/Security/MemberUserStore.cs
@@ -574,7 +574,7 @@ namespace Umbraco.Cms.Core.Security
                 throw new ArgumentNullException(nameof(user));
             }
 
-            IIdentityUserToken token = user.LoginTokens.FirstOrDefault(x => x.LoginProvider.InvariantEquals(loginProvider) && x.Name.InvariantEquals(name));
+            IIdentityUserToken? token = user.LoginTokens.FirstOrDefault(x => x.LoginProvider.InvariantEquals(loginProvider) && x.Name.InvariantEquals(name));
             if (token == null)
             {
                 user.LoginTokens.Add(new IdentityUserToken(loginProvider, name, value, user.Id));
@@ -587,7 +587,7 @@ namespace Umbraco.Cms.Core.Security
             return Task.CompletedTask;
         }
 
-        private MemberIdentityUser AssignLoginsCallback(MemberIdentityUser? user)
+        private MemberIdentityUser? AssignLoginsCallback(MemberIdentityUser? user)
         {
             if (user != null)
             {