diff -rupN --no-dereference freetype-2.10.1/include/freetype/ftoutln.h freetype-2.10.1-new/include/freetype/ftoutln.h
--- freetype-2.10.1/include/freetype/ftoutln.h	2019-06-23 07:01:12.000000000 +0200
+++ freetype-2.10.1-new/include/freetype/ftoutln.h	2020-02-07 17:45:38.812222868 +0100
@@ -165,6 +165,15 @@ FT_BEGIN_HEADER
                   FT_Int       numContours,
                   FT_Outline  *anoutline );
 
+  /*
+   * Kept downstream for ABI compatibility only.
+   * It just throws error now. Remove once soname has been bumped.
+   */
+  FT_EXPORT( FT_Error )
+  FT_Outline_New_Internal( FT_Memory    memory,
+                           FT_UInt      numPoints,
+                           FT_Int       numContours,
+                           FT_Outline  *anoutline );
 
   /**************************************************************************
    *
@@ -192,6 +201,13 @@ FT_BEGIN_HEADER
   FT_Outline_Done( FT_Library   library,
                    FT_Outline*  outline );
 
+  /*
+   * Kept downstream for ABI compatibility only.
+   * It just throws error now. Remove once soname has been bumped.
+   */
+  FT_EXPORT( FT_Error )
+  FT_Outline_Done_Internal( FT_Memory    memory,
+                            FT_Outline*  outline );
 
   /**************************************************************************
    *
diff -rupN --no-dereference freetype-2.10.1/src/base/ftoutln.c freetype-2.10.1-new/src/base/ftoutln.c
--- freetype-2.10.1/src/base/ftoutln.c	2019-05-12 21:07:18.000000000 +0200
+++ freetype-2.10.1-new/src/base/ftoutln.c	2020-02-07 17:45:38.812222868 +0100
@@ -290,6 +290,19 @@
 
   /* documentation is in ftoutln.h */
 
+  /*
+   * Kept downstream for ABI compatibility only.
+   * It just throws error now. Remove once soname has been bumped.
+   */
+  FT_EXPORT_DEF( FT_Error )
+  FT_Outline_New_Internal( FT_Memory    memory,
+                           FT_UInt      numPoints,
+                           FT_Int       numContours,
+                           FT_Outline  *anoutline )
+  {
+    return FT_THROW( Unimplemented_Feature );
+  }
+
   FT_EXPORT_DEF( FT_Error )
   FT_Outline_New( FT_Library   library,
                   FT_UInt      numPoints,
@@ -422,6 +435,17 @@
 
   /* documentation is in ftoutln.h */
 
+  /*
+   * Kept downstream for ABI compatibility only.
+   * It just throws error now. Remove once soname has been bumped.
+   */
+  FT_EXPORT_DEF( FT_Error )
+  FT_Outline_Done_Internal( FT_Memory    memory,
+                            FT_Outline*  outline )
+  {
+    return FT_THROW( Unimplemented_Feature );
+  }
+
   FT_EXPORT_DEF( FT_Error )
   FT_Outline_Done( FT_Library   library,
                    FT_Outline*  outline )