diff --git a/src/Microsoft.AspNetCore.Http.Features/Microsoft.AspNetCore.Http.Features.csproj b/src/Microsoft.AspNetCore.Http.Features/Microsoft.AspNetCore.Http.Features.csproj
index 1920b47231..a6ebb2411f 100644
--- a/src/Microsoft.AspNetCore.Http.Features/Microsoft.AspNetCore.Http.Features.csproj
+++ b/src/Microsoft.AspNetCore.Http.Features/Microsoft.AspNetCore.Http.Features.csproj
@@ -8,7 +8,6 @@
     <NoWarn>$(NoWarn);CS1591</NoWarn>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>aspnetcore</PackageTags>
-    <EnableApiCheck>false</EnableApiCheck>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/Microsoft.AspNetCore.Http.Features/breakingchanges.netcore.json b/src/Microsoft.AspNetCore.Http.Features/breakingchanges.netcore.json
new file mode 100644
index 0000000000..7bdc58b355
--- /dev/null
+++ b/src/Microsoft.AspNetCore.Http.Features/breakingchanges.netcore.json
@@ -0,0 +1,12 @@
+[
+  {
+    "TypeId": "public interface Microsoft.AspNetCore.Http.IHeaderDictionary : System.Collections.Generic.IDictionary<System.String, Microsoft.Extensions.Primitives.StringValues>",
+    "MemberId": "System.Nullable<System.Int64> get_ContentLength()",
+    "Kind": "Addition"
+  },
+  {
+    "TypeId": "public interface Microsoft.AspNetCore.Http.IHeaderDictionary : System.Collections.Generic.IDictionary<System.String, Microsoft.Extensions.Primitives.StringValues>",
+    "MemberId": "System.Void set_ContentLength(System.Nullable<System.Int64> value)",
+    "Kind": "Addition"
+  }
+]
\ No newline at end of file
diff --git a/src/Microsoft.AspNetCore.Http.Features/exceptions.netcore.json b/src/Microsoft.AspNetCore.Http.Features/exceptions.netcore.json
deleted file mode 100644
index e312fab8bd..0000000000
--- a/src/Microsoft.AspNetCore.Http.Features/exceptions.netcore.json
+++ /dev/null
@@ -1,14 +0,0 @@
-[
-  {
-    "OldTypeId": "public interface Microsoft.AspNetCore.Http.IHeaderDictionary : System.Collections.Generic.IDictionary<System.String, Microsoft.Extensions.Primitives.StringValues>",
-    "NewTypeId": "public interface Microsoft.AspNetCore.Http.IHeaderDictionary : System.Collections.Generic.IDictionary<System.String, Microsoft.Extensions.Primitives.StringValues>",
-    "NewMemberId": "System.Nullable<System.Int64> get_ContentLength()",
-    "Kind": "Addition"
-  },
-  {
-    "OldTypeId": "public interface Microsoft.AspNetCore.Http.IHeaderDictionary : System.Collections.Generic.IDictionary<System.String, Microsoft.Extensions.Primitives.StringValues>",
-    "NewTypeId": "public interface Microsoft.AspNetCore.Http.IHeaderDictionary : System.Collections.Generic.IDictionary<System.String, Microsoft.Extensions.Primitives.StringValues>",
-    "NewMemberId": "System.Void set_ContentLength(System.Nullable<System.Int64> value)",
-    "Kind": "Addition"
-  }
-]
\ No newline at end of file
diff --git a/src/Microsoft.Net.Http.Headers/Microsoft.Net.Http.Headers.csproj b/src/Microsoft.Net.Http.Headers/Microsoft.Net.Http.Headers.csproj
index e86898c885..521dd7caa1 100644
--- a/src/Microsoft.Net.Http.Headers/Microsoft.Net.Http.Headers.csproj
+++ b/src/Microsoft.Net.Http.Headers/Microsoft.Net.Http.Headers.csproj
@@ -9,7 +9,6 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>http</PackageTags>
-    <EnableApiCheck>false</EnableApiCheck>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/Microsoft.Net.Http.Headers/breakingchanges.netcore.json b/src/Microsoft.Net.Http.Headers/breakingchanges.netcore.json
new file mode 100644
index 0000000000..6748ae1f1e
--- /dev/null
+++ b/src/Microsoft.Net.Http.Headers/breakingchanges.netcore.json
@@ -0,0 +1,412 @@
+[
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentDispositionHeaderValue",
+    "MemberId": "public .ctor(System.String dispositionType)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentDispositionHeaderValue",
+    "MemberId": "public static Microsoft.Net.Http.Headers.ContentDispositionHeaderValue Parse(System.String input)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentDispositionHeaderValue",
+    "MemberId": "public static System.Boolean TryParse(System.String input, out Microsoft.Net.Http.Headers.ContentDispositionHeaderValue parsedValue)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentDispositionHeaderValue",
+    "MemberId": "public System.String get_DispositionType()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentDispositionHeaderValue",
+    "MemberId": "public System.String get_FileName()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentDispositionHeaderValue",
+    "MemberId": "public System.String get_FileNameStar()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentDispositionHeaderValue",
+    "MemberId": "public System.String get_Name()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentDispositionHeaderValue",
+    "MemberId": "public System.Void set_DispositionType(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentDispositionHeaderValue",
+    "MemberId": "public System.Void set_FileName(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentDispositionHeaderValue",
+    "MemberId": "public System.Void set_FileNameStar(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentDispositionHeaderValue",
+    "MemberId": "public System.Void set_Name(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentDispositionHeaderValue",
+    "MemberId": "public System.Void SetHttpFileName(System.String fileName)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentDispositionHeaderValue",
+    "MemberId": "public System.Void SetMimeFileName(System.String fileName)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.MediaTypeHeaderValue",
+    "MemberId": "public .ctor(System.String mediaType)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.MediaTypeHeaderValue",
+    "MemberId": "public .ctor(System.String mediaType, System.Double quality)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.MediaTypeHeaderValue",
+    "MemberId": "public static Microsoft.Net.Http.Headers.MediaTypeHeaderValue Parse(System.String input)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.MediaTypeHeaderValue",
+    "MemberId": "public static System.Boolean TryParse(System.String input, out Microsoft.Net.Http.Headers.MediaTypeHeaderValue parsedValue)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.MediaTypeHeaderValue",
+    "MemberId": "public System.String get_Boundary()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.MediaTypeHeaderValue",
+    "MemberId": "public System.String get_Charset()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.MediaTypeHeaderValue",
+    "MemberId": "public System.String get_MediaType()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.MediaTypeHeaderValue",
+    "MemberId": "public System.String get_SubType()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.MediaTypeHeaderValue",
+    "MemberId": "public System.String get_Type()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.MediaTypeHeaderValue",
+    "MemberId": "public System.Void set_Boundary(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.MediaTypeHeaderValue",
+    "MemberId": "public System.Void set_Charset(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.MediaTypeHeaderValue",
+    "MemberId": "public System.Void set_MediaType(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.CookieHeaderValue",
+    "MemberId": "public .ctor(System.String name)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.CookieHeaderValue",
+    "MemberId": "public .ctor(System.String name, System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.CookieHeaderValue",
+    "MemberId": "public static Microsoft.Net.Http.Headers.CookieHeaderValue Parse(System.String input)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.CookieHeaderValue",
+    "MemberId": "public static System.Boolean TryParse(System.String input, out Microsoft.Net.Http.Headers.CookieHeaderValue parsedValue)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.CookieHeaderValue",
+    "MemberId": "public System.String get_Name()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.CookieHeaderValue",
+    "MemberId": "public System.String get_Value()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.CookieHeaderValue",
+    "MemberId": "public System.Void set_Name(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.CookieHeaderValue",
+    "MemberId": "public System.Void set_Value(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.NameValueHeaderValue",
+    "MemberId": "public .ctor(System.String name)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.NameValueHeaderValue",
+    "MemberId": "public .ctor(System.String name, System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.NameValueHeaderValue",
+    "MemberId": "public static Microsoft.Net.Http.Headers.NameValueHeaderValue Find(System.Collections.Generic.IList<Microsoft.Net.Http.Headers.NameValueHeaderValue> values, System.String name)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.NameValueHeaderValue",
+    "MemberId": "public static Microsoft.Net.Http.Headers.NameValueHeaderValue Parse(System.String input)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.NameValueHeaderValue",
+    "MemberId": "public static System.Boolean TryParse(System.String input, out Microsoft.Net.Http.Headers.NameValueHeaderValue parsedValue)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.NameValueHeaderValue",
+    "MemberId": "public System.String get_Name()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.NameValueHeaderValue",
+    "MemberId": "public System.String get_Value()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.NameValueHeaderValue",
+    "MemberId": "public System.Void set_Value(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.SetCookieHeaderValue",
+    "MemberId": "public .ctor(System.String name)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.SetCookieHeaderValue",
+    "MemberId": "public .ctor(System.String name, System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.SetCookieHeaderValue",
+    "MemberId": "public static Microsoft.Net.Http.Headers.SetCookieHeaderValue Parse(System.String input)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.SetCookieHeaderValue",
+    "MemberId": "public static System.Boolean TryParse(System.String input, out Microsoft.Net.Http.Headers.SetCookieHeaderValue parsedValue)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.SetCookieHeaderValue",
+    "MemberId": "public System.String get_Domain()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.SetCookieHeaderValue",
+    "MemberId": "public System.String get_Name()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.SetCookieHeaderValue",
+    "MemberId": "public System.String get_Path()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.SetCookieHeaderValue",
+    "MemberId": "public System.String get_Value()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.SetCookieHeaderValue",
+    "MemberId": "public System.Void set_Domain(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.SetCookieHeaderValue",
+    "MemberId": "public System.Void set_Name(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.SetCookieHeaderValue",
+    "MemberId": "public System.Void set_Path(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.SetCookieHeaderValue",
+    "MemberId": "public System.Void set_Value(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.EntityTagHeaderValue",
+    "MemberId": "public .ctor(System.String tag)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.EntityTagHeaderValue",
+    "MemberId": "public .ctor(System.String tag, System.Boolean isWeak)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.EntityTagHeaderValue",
+    "MemberId": "public static Microsoft.Net.Http.Headers.EntityTagHeaderValue Parse(System.String input)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.EntityTagHeaderValue",
+    "MemberId": "public static System.Boolean TryParse(System.String input, out Microsoft.Net.Http.Headers.EntityTagHeaderValue parsedValue)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.EntityTagHeaderValue",
+    "MemberId": "public System.String get_Tag()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.StringWithQualityHeaderValue",
+    "MemberId": "public .ctor(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.StringWithQualityHeaderValue",
+    "MemberId": "public .ctor(System.String value, System.Double quality)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.StringWithQualityHeaderValue",
+    "MemberId": "public static Microsoft.Net.Http.Headers.StringWithQualityHeaderValue Parse(System.String input)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.StringWithQualityHeaderValue",
+    "MemberId": "public static System.Boolean TryParse(System.String input, out Microsoft.Net.Http.Headers.StringWithQualityHeaderValue parsedValue)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.StringWithQualityHeaderValue",
+    "MemberId": "public System.String get_Value()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public static class Microsoft.Net.Http.Headers.HeaderNames",
+    "MemberId": "public const System.String ContentMD5 = \"ContentMD5\"",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.CacheControlHeaderValue",
+    "MemberId": "public static Microsoft.Net.Http.Headers.CacheControlHeaderValue Parse(System.String input)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.CacheControlHeaderValue",
+    "MemberId": "public static System.Boolean TryParse(System.String input, out Microsoft.Net.Http.Headers.CacheControlHeaderValue parsedValue)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.CacheControlHeaderValue",
+    "MemberId": "public System.Collections.Generic.ICollection<System.String> get_NoCacheHeaders()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.CacheControlHeaderValue",
+    "MemberId": "public System.Collections.Generic.ICollection<System.String> get_PrivateHeaders()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentRangeHeaderValue",
+    "MemberId": "public static Microsoft.Net.Http.Headers.ContentRangeHeaderValue Parse(System.String input)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentRangeHeaderValue",
+    "MemberId": "public static System.Boolean TryParse(System.String input, out Microsoft.Net.Http.Headers.ContentRangeHeaderValue parsedValue)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentRangeHeaderValue",
+    "MemberId": "public System.String get_Unit()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.ContentRangeHeaderValue",
+    "MemberId": "public System.Void set_Unit(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.RangeConditionHeaderValue",
+    "MemberId": "public static Microsoft.Net.Http.Headers.RangeConditionHeaderValue Parse(System.String input)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.RangeConditionHeaderValue",
+    "MemberId": "public static System.Boolean TryParse(System.String input, out Microsoft.Net.Http.Headers.RangeConditionHeaderValue parsedValue)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.RangeHeaderValue",
+    "MemberId": "public static Microsoft.Net.Http.Headers.RangeHeaderValue Parse(System.String input)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.RangeHeaderValue",
+    "MemberId": "public static System.Boolean TryParse(System.String input, out Microsoft.Net.Http.Headers.RangeHeaderValue parsedValue)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.RangeHeaderValue",
+    "MemberId": "public System.String get_Unit()",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public class Microsoft.Net.Http.Headers.RangeHeaderValue",
+    "MemberId": "public System.Void set_Unit(System.String value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public static class Microsoft.Net.Http.Headers.HeaderUtilities",
+    "MemberId": "public static System.Boolean TryParseDate(System.String input, out System.DateTimeOffset result)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public static class Microsoft.Net.Http.Headers.HeaderUtilities",
+    "MemberId": "public static System.Boolean TryParseInt64(System.String value, out System.Int64 result)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public static class Microsoft.Net.Http.Headers.HeaderUtilities",
+    "MemberId": "public static System.String FormatInt64(System.Int64 value)",
+    "Kind": "Removal"
+  },
+  {
+    "TypeId": "public static class Microsoft.Net.Http.Headers.HeaderUtilities",
+    "MemberId": "public static System.String RemoveQuotes(System.String input)",
+    "Kind": "Removal"
+  }
+]
\ No newline at end of file