diff --git a/src/demux/demux.c b/src/demux/demux.c
index c098119a..d716f10f 100644
--- a/src/demux/demux.c
+++ b/src/demux/demux.c
@@ -757,6 +757,7 @@ static const Frame* GetFrame(const WebPDemuxer* const dmux, int frame_num) {
 }
 
 // Returns fragment 'fragment_num' and the total count.
+// TODO(jzern): this function is no longer necessary.
 static const Frame* GetFragment(
     const Frame* const frame_set, int fragment_num, int* const count) {
   const int this_frame = frame_set->frame_num_;
@@ -811,8 +812,6 @@ static int SynthesizeFrame(const WebPDemuxer* const dmux,
 
   iter->frame_num      = first_frame->frame_num_;
   iter->num_frames     = dmux->num_frames_;
-  iter->fragment_num   = fragment_num;
-  iter->num_fragments  = num_fragments;
   iter->x_offset       = fragment->x_offset_;
   iter->y_offset       = fragment->y_offset_;
   iter->width          = fragment->width_;
diff --git a/src/webp/demux.h b/src/webp/demux.h
index f90e2354..b4ed19d5 100644
--- a/src/webp/demux.h
+++ b/src/webp/demux.h
@@ -55,7 +55,7 @@
 extern "C" {
 #endif
 
-#define WEBP_DEMUX_ABI_VERSION 0x0106    // MAJOR(8b) + MINOR(8b)
+#define WEBP_DEMUX_ABI_VERSION 0x0107    // MAJOR(8b) + MINOR(8b)
 
 // Note: forward declaring enumerations is not allowed in (strict) C and C++,
 // the types are left here for reference.
@@ -137,17 +137,15 @@ WEBP_EXTERN(uint32_t) WebPDemuxGetI(
 struct WebPIterator {
   int frame_num;
   int num_frames;          // equivalent to WEBP_FF_FRAME_COUNT.
-  int fragment_num;
-  int num_fragments;
   int x_offset, y_offset;  // offset relative to the canvas.
-  int width, height;       // dimensions of this frame or fragment.
+  int width, height;       // dimensions of this frame.
   int duration;            // display duration in milliseconds.
   WebPMuxAnimDispose dispose_method;  // dispose method for the frame.
   int complete;   // true if 'fragment' contains a full frame. partial images
                   // may still be decoded with the WebP incremental decoder.
-  WebPData fragment;  // The frame or fragment given by 'frame_num' and
-                      // 'fragment_num'.
-  int has_alpha;      // True if the frame or fragment contains transparency.
+  WebPData fragment;  // The frame given by 'frame_num'. Note for historical
+                      // reasons this is called a fragment.
+  int has_alpha;      // True if the frame contains transparency.
   WebPMuxAnimBlend blend_method;  // Blend operation for the frame.
 
   uint32_t pad[2];         // padding for later use.