diff --git a/plugins/messageviewer/bodypartformatter/gnupgwks/gnupgwks.json b/plugins/messageviewer/bodypartformatter/gnupgwks/gnupgwks.json
--- a/plugins/messageviewer/bodypartformatter/gnupgwks/gnupgwks.json
+++ b/plugins/messageviewer/bodypartformatter/gnupgwks/gnupgwks.json
@@ -1,10 +1,10 @@
 {
     "formatter": [
+        { "mimetype": "application/pgp-keys" },
         { "mimetype": "multipart/mixed" },
-        { "mimetype": "application/vnd.gnupg.wks" },
-        { "mimetype": "application/pgp-keys" }
+        { "mimetype": "application/vnd.gnupg.wks" }
     ],
     "renderer": [
-        { "type": "MimeTreeParser::AttachmentMessagePart" }
+        { "type": "PgpKeyMessagePart" }
     ]
 }
diff --git a/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeyformatter.h b/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeyformatter.h
--- a/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeyformatter.h
+++ b/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeyformatter.h
@@ -21,15 +21,19 @@
 #define PGPKEYFORMATTER_H_
 
 #include <MimeTreeParser/BodyPartFormatter>
+#include <MessageViewer/MessagePartRendererBase>
 
 class PgpKeyMessagePart;
 
-class ApplicationPGPKeyFormatter : public MimeTreeParser::Interface::BodyPartFormatter
+class ApplicationPGPKeyFormatter
+    : public MimeTreeParser::Interface::BodyPartFormatter
+    , public MessageViewer::MessagePartRendererBase
 {
 public:
     ApplicationPGPKeyFormatter() = default;
 
-    MimeTreeParser::Interface::BodyPartFormatter::Result format(MimeTreeParser::Interface::BodyPart *part, MimeTreeParser::HtmlWriter *writer) const override;
+    MimeTreeParser::MessagePartPtr process(MimeTreeParser::Interface::BodyPart & part) const override;
+    bool render(const MimeTreeParser::MessagePartPtr &msgPart, MimeTreeParser::HtmlWriter *htmlWriter, MessageViewer::RenderContext *context) const override;
 
 private:
     QString render(const PgpKeyMessagePart &mp) const;
diff --git a/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeyformatter.cpp b/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeyformatter.cpp
--- a/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeyformatter.cpp
+++ b/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeyformatter.cpp
@@ -35,44 +35,43 @@
 
 using namespace MimeTreeParser::Interface;
 
-BodyPartFormatter::Result ApplicationPGPKeyFormatter::format(BodyPart *part, MimeTreeParser::HtmlWriter *writer) const
+MimeTreeParser::MessagePartPtr ApplicationPGPKeyFormatter::process(MimeTreeParser::Interface::BodyPart& part) const
 {
-    if (!writer) {
-        return Ok;
-    }
-
-    PgpKeyMemento *m = dynamic_cast<PgpKeyMemento *>(part->memento());
-    PgpKeyMessagePart mp(part);
+    auto mp = new PgpKeyMessagePart(&part);
+    PgpKeyMemento *m = dynamic_cast<PgpKeyMemento *>(mp->memento());
 
     if (!m) {
         auto memento = new PgpKeyMemento();
-        auto nodeHelper = part->nodeHelper();
+        auto nodeHelper = part.nodeHelper();
         if (nodeHelper) {
             QObject::connect(memento, &PgpKeyMemento::update,
                              nodeHelper, &MimeTreeParser::NodeHelper::update);
-            memento->start(mp.fingerprint());
+            memento->start(mp->fingerprint());
         } else {
-            memento->exec(mp.fingerprint());
+            memento->exec(mp->fingerprint());
             m = memento;
         }
-        part->setBodyPartMemento(memento);
+        mp->setMemento(memento);
     } else if (m->isRunning()) {
         m = nullptr;
     }
 
     if (m) {
         Q_ASSERT(!m->isRunning());
 
-        mp.setError(m->error());
-        mp.setKey(m->key());
+        mp->setError(m->error());
+        mp->setKey(m->key());
     }
-
-    writer->write(render(mp));
-    return Ok;
+    return MimeTreeParser::MessagePartPtr(mp);
 }
 
-QString ApplicationPGPKeyFormatter::render(const PgpKeyMessagePart &mp) const
+bool ApplicationPGPKeyFormatter::render(const MimeTreeParser::MessagePartPtr &msgPart, MimeTreeParser::HtmlWriter *htmlWriter, MessageViewer::RenderContext *context) const
 {
+    Q_UNUSED(context);
+    auto mp = msgPart.dynamicCast<PgpKeyMessagePart>();
+    if (!mp)
+        return false;
+
     GrantleeTheme::Engine engine;
     engine.localizer()->setApplicationDomain(QByteArrayLiteral("messageviewer_application_gnupgwks_plugin"));
     engine.addTemplateLoader(QSharedPointer<GrantleeTheme::QtResourceTemplateLoader>::create());
@@ -83,14 +82,14 @@
 
     QObject block;
 
-    block.setProperty("showKeyDetails", mp.source()->showSignatureDetails());
-    block.setProperty("error", mp.error());
-    block.setProperty("importUrl", mp.part()->makeLink(QStringLiteral("pgpkey")) + QStringLiteral("?action=import"));
-    const auto key = mp.key();
+    block.setProperty("showKeyDetails", mp->source()->showSignatureDetails());
+    block.setProperty("error", mp->error());
+    block.setProperty("importUrl", mp->makeLink(QStringLiteral("pgpkey")) + QStringLiteral("?action=import"));
+    const auto key = mp->key();
     if (key.isNull()) {
-        block.setProperty("uid", mp.userID());
-        block.setProperty("fingerprint", mp.fingerprint());
-        block.setProperty("created", mp.keyDate().toString(Qt::SystemLocaleDate));
+        block.setProperty("uid", mp->userID());
+        block.setProperty("fingerprint", mp->fingerprint());
+        block.setProperty("created", mp->keyDate().toString(Qt::SystemLocaleDate));
     } else {
         const auto uid = key.userID(0);
         block.setProperty("hasKey", true);
@@ -121,5 +120,7 @@
 
     ctx.insert(QStringLiteral("block"), &block);
     ctx.insert(QStringLiteral("style"), &style);
-    return tpl->render(&ctx);
+    Grantlee::OutputStream s(htmlWriter->stream());
+    tpl->render(&s, &ctx);
+    return true;
 }
diff --git a/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeymessagepart.h b/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeymessagepart.h
--- a/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeymessagepart.h
+++ b/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeymessagepart.h
@@ -20,6 +20,8 @@
 #ifndef PGPKEYMESSAGEPART_H_
 #define PGPKEYMESSAGEPART_H_
 
+#include <MimeTreeParser/MessagePart>
+
 #include <QDateTime>
 #include <QString>
 
@@ -35,12 +37,12 @@
 class Content;
 }
 
-class PgpKeyMessagePart
+class PgpKeyMessagePart : public MimeTreeParser::MessagePart
 {
+    Q_OBJECT
 public:
-    PgpKeyMessagePart(MimeTreeParser::Interface::BodyPart *part);
-
-    virtual ~PgpKeyMessagePart() = default;
+    explicit PgpKeyMessagePart(MimeTreeParser::Interface::BodyPart *part);
+    ~PgpKeyMessagePart() = default;
 
     QDateTime keyDate() const;
     QString userID() const;
@@ -55,13 +57,9 @@
 
     QByteArray rawKey() const;
 
-    MimeTreeParser::Interface::ObjectTreeSource *source() const;
-    MimeTreeParser::Interface::BodyPart *part() const;
-
 protected:
     void parseContent(KMime::Content *node);
 
-    MimeTreeParser::Interface::BodyPart *mPart = nullptr;
     QDateTime mKeyDate;
     QString mUserID;
     QString mKeyID;
diff --git a/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeymessagepart.cpp b/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeymessagepart.cpp
--- a/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeymessagepart.cpp
+++ b/plugins/messageviewer/bodypartformatter/gnupgwks/pgpkeymessagepart.cpp
@@ -25,9 +25,10 @@
 #include <KMime/Content>
 
 PgpKeyMessagePart::PgpKeyMessagePart(MimeTreeParser::Interface::BodyPart *part)
-    : mPart(part)
+    : MimeTreeParser::MessagePart(part->objectTreeParser(), QString())
 {
-    parseContent(mPart->content());
+    setContent(part->content());
+    parseContent(part->content());
 }
 
 QDateTime PgpKeyMessagePart::keyDate() const
@@ -72,17 +73,7 @@
 
 QByteArray PgpKeyMessagePart::rawKey() const
 {
-    return mPart->content()->decodedContent();
-}
-
-MimeTreeParser::Interface::ObjectTreeSource *PgpKeyMessagePart::source() const
-{
-    return mPart->source();
-}
-
-MimeTreeParser::Interface::BodyPart *PgpKeyMessagePart::part() const
-{
-    return mPart;
+    return content()->decodedContent();
 }
 
 void PgpKeyMessagePart::parseContent(KMime::Content *node)
diff --git a/plugins/messageviewer/bodypartformatter/gnupgwks/plugin.cpp b/plugins/messageviewer/bodypartformatter/gnupgwks/plugin.cpp
--- a/plugins/messageviewer/bodypartformatter/gnupgwks/plugin.cpp
+++ b/plugins/messageviewer/bodypartformatter/gnupgwks/plugin.cpp
@@ -26,9 +26,9 @@
 
 namespace {
 enum Index {
+    application_pgp_keys,
     multipart_mixed,
-    application_vnd_gnupg_keys,
-    application_pgp_keys
+    application_vnd_gnupg_keys
 };
 }
 
@@ -45,10 +45,17 @@
     }
 }
 
-MessageViewer::MessagePartRendererBase* ApplicationGnuPGWKSPlugin::renderer(int index)
+MessageViewer::MessagePartRendererBase* ApplicationGnuPGWKSPlugin::renderer(int idx)
 {
-    Q_UNUSED(index);
-    return nullptr;
+    switch (idx) {
+    case multipart_mixed:
+    case application_vnd_gnupg_keys:
+        return nullptr; // TODO
+    case application_pgp_keys:
+        return new ApplicationPGPKeyFormatter();
+    default:
+        return nullptr;
+    }
 }
 
 const MessageViewer::Interface::BodyPartURLHandler *ApplicationGnuPGWKSPlugin::urlHandler(int idx) const