diff --git a/plugins/messageviewer/bodypartformatter/xdiff/text_xdiff.cpp b/plugins/messageviewer/bodypartformatter/xdiff/text_xdiff.cpp
--- a/plugins/messageviewer/bodypartformatter/xdiff/text_xdiff.cpp
+++ b/plugins/messageviewer/bodypartformatter/xdiff/text_xdiff.cpp
@@ -32,21 +32,25 @@
 #include "diffhighlighter.h"
 
 #include <MessageViewer/BodyPartURLHandler>
+#include <MessageViewer/MessagePartRendererBase>
+#include <MessageViewer/MessagePartRenderPlugin>
 #include <MimeTreeParser/BodyPartFormatter>
 #include <MimeTreeParser/BodyPart>
+#include <MimeTreeParser/MessagePart>
 #include <MimeTreeParser/HtmlWriter>
 
 #include <kstringhandler.h>
 
 namespace {
 // TODO: Show filename header to make it possible to save the patch.
 // FIXME: The box should only be as wide as necessary.
 
-class Formatter : public MimeTreeParser::Interface::BodyPartFormatter
+class Formatter : public MimeTreeParser::Interface::BodyPartFormatter, public MessageViewer::MessagePartRendererBase
 {
 public:
     Result format(MimeTreeParser::Interface::BodyPart *bodyPart, MimeTreeParser::HtmlWriter *writer) const override
     {
+        return Failed;
         if (!writer) {
             return Ok;
         }
@@ -68,14 +72,35 @@
         return Ok;
     }
 
-    // unhide the overload with three arguments
-    using MimeTreeParser::Interface::BodyPartFormatter::format;
+    bool render(const MimeTreeParser::MessagePartPtr &msgPart, MimeTreeParser::HtmlWriter *htmlWriter, MessageViewer::RenderContext *context) const override
+    {
+        auto mp = msgPart.dynamicCast<MimeTreeParser::AttachmentMessagePart>();
+        if (!mp || mp->isHidden()) // TODO check for inline vs. icon
+            return false;
+
+        const bool diffMimeType = msgPart->content()->contentType()->mimeType() == "text/x-patch"
+                               || msgPart->content()->contentType()->mimeType() == "text/x-diff";
+        const bool diffFileName = msgPart->content()->contentType()->name().endsWith(QLatin1String(".diff"))
+                               || msgPart->content()->contentType()->name().endsWith(QLatin1String(".patch"));
+        if (!diffMimeType && !diffFileName)
+            return false;
+
+        // TODO attachment block
+
+        DiffHighlighter highLighter;
+        highLighter.highlightDiff(msgPart->text());
+        const QString html = highLighter.outputDiff();
+        htmlWriter->write(html);
+
+        return true;
+    }
 };
 
-class Plugin : public QObject, public MimeTreeParser::Interface::BodyPartFormatterPlugin
+class Plugin : public QObject, public MimeTreeParser::Interface::BodyPartFormatterPlugin, public MessageViewer::MessagePartRenderPlugin
 {
     Q_OBJECT
     Q_INTERFACES(MimeTreeParser::Interface::BodyPartFormatterPlugin)
+    Q_INTERFACES(MessageViewer::MessagePartRenderPlugin)
     Q_PLUGIN_METADATA(IID "com.kde.messageviewer.bodypartformatter" FILE "text_xdiff.json")
 public:
     const MimeTreeParser::Interface::BodyPartFormatter *bodyPartFormatter(int idx) const override
@@ -85,6 +110,13 @@
         }
         return nullptr;
     }
+
+    MessageViewer::MessagePartRendererBase* renderer(int index) override
+    {
+        if (index == 0)
+            return new Formatter();
+        return nullptr;
+    }
 };
 }
 
diff --git a/plugins/messageviewer/bodypartformatter/xdiff/text_xdiff.json b/plugins/messageviewer/bodypartformatter/xdiff/text_xdiff.json
--- a/plugins/messageviewer/bodypartformatter/xdiff/text_xdiff.json
+++ b/plugins/messageviewer/bodypartformatter/xdiff/text_xdiff.json
@@ -1,5 +1,4 @@
-{ "formatter":
-    [
-        { "mimetype": "text/x-patch" }
-    ]
+{
+    "formatter": [ { "mimetype": "text/x-patch" } ],
+    "renderer": [ { "type": "MimeTreeParser::AttachmentMessagePart" } ]
 }