diff --git a/messageviewer/CMakeLists.txt b/messageviewer/CMakeLists.txt
--- a/messageviewer/CMakeLists.txt
+++ b/messageviewer/CMakeLists.txt
@@ -37,6 +37,34 @@
   DESTINATION ${KDE_INSTALL_INCLUDEDIR_KF5} COMPONENT Devel
 )
 
+ecm_setup_version(${MESSAGELIB_LIB_VERSION} VARIABLE_PREFIX MESSAGEVIEWER
+                        VERSION_HEADER "${CMAKE_CURRENT_BINARY_DIR}/otp_version.h"
+                        PACKAGE_VERSION_FILE "${CMAKE_CURRENT_BINARY_DIR}/KF5OtpConfigVersion.cmake"
+                        SOVERSION 5
+)
+
+set(CMAKECONFIG_INSTALL_DIR "${KDE_INSTALL_CMAKEPACKAGEDIR}/KF5Otp")
+
+ecm_configure_package_config_file(
+  "${CMAKE_CURRENT_SOURCE_DIR}/KF5OtpConfig.cmake.in"
+  "${CMAKE_CURRENT_BINARY_DIR}/KF5OtpConfig.cmake"
+  INSTALL_DESTINATION  ${CMAKECONFIG_INSTALL_DIR}
+)
+
+install(FILES
+  "${CMAKE_CURRENT_BINARY_DIR}/KF5OtpConfig.cmake"
+  "${CMAKE_CURRENT_BINARY_DIR}/KF5OtpConfigVersion.cmake"
+  DESTINATION "${CMAKECONFIG_INSTALL_DIR}"
+  COMPONENT Devel
+)
+
+install(EXPORT KF5OtpTargets DESTINATION "${CMAKECONFIG_INSTALL_DIR}" FILE KF5OtpTargets.cmake NAMESPACE KF5::)
+
+install(FILES
+   ${CMAKE_CURRENT_BINARY_DIR}/otp_version.h
+  DESTINATION ${KDE_INSTALL_INCLUDEDIR_KF5} COMPONENT Devel
+)
+
 add_subdirectory(src)
 if (BUILD_TESTING)
    add_subdirectory(autotests)
diff --git a/messageviewer/KF5OtpConfig.cmake.in b/messageviewer/KF5OtpConfig.cmake.in
new file mode 100644
--- /dev/null
+++ b/messageviewer/KF5OtpConfig.cmake.in
@@ -0,0 +1,7 @@
+@PACKAGE_INIT@
+
+find_dependency(KF5PimCommon "@PIMCOMMON_LIB_VERSION@")
+find_dependency(KF5MessageCore "@MESSAGELIB_LIB_VERSION@")
+find_dependency(KF5Mime "@KMIME_LIB_VERSION@")
+
+include("${CMAKE_CURRENT_LIST_DIR}/KF5OtpTargets.cmake")
diff --git a/messageviewer/src/CMakeLists.txt b/messageviewer/src/CMakeLists.txt
--- a/messageviewer/src/CMakeLists.txt
+++ b/messageviewer/src/CMakeLists.txt
@@ -85,6 +85,37 @@
    set(libmessageviewer_web_LIB Qt5::WebEngine Qt5::WebEngineWidgets ${libmessageviewer_web_LIB})
 endif()
 
+set(libmessageviewer_otp_SRCS
+  interfaces/bodypartformatter.cpp
+  viewer/bodypartformatter.cpp
+  viewer/bodypartformatterfactory.cpp
+  viewer/cryptohelper.cpp
+  viewer/nodehelper.cpp
+  viewer/objecttreeparser.cpp
+  viewer/messagepart.cpp
+  viewer/partnodebodypart.cpp
+  viewer/pluginloaderbase.cpp
+  viewer/memento/cryptobodypartmemento.cpp
+  viewer/memento/decryptverifybodypartmemento.cpp
+  viewer/memento/verifydetachedbodypartmemento.cpp
+  viewer/memento/verifyopaquebodypartmemento.cpp
+)
+
+set(libmessageviewer_otp_extra_SRCS
+  job/kleojobexecutor.cpp
+  #for quotes
+  viewer/csshelperbase.cpp # only interface without settings
+  viewer/csshelper.cpp
+  viewer/attachmentstrategy.cpp
+  utils/iconnamecache.cpp
+  utils/mimetype.cpp
+  viewer/converthtmltoplaintext.cpp
+  viewer/urlhandlermanager_otp.cpp
+  #HTML Writer
+  htmlwriter/filehtmlwriter.cpp
+  htmlwriter/queuehtmlwriter.cpp
+)
+
 set(libmessageviewer_viewer_SRCS
   viewer/attachmentstrategy.cpp
   viewer/bodypartformatter.cpp
@@ -164,6 +195,7 @@
   utils/iconnamecache.cpp
   utils/markmessagereadhandler.cpp
   utils/messageviewerutil.cpp
+  utils/mimetype.cpp
 )
 
 set(libmessageviewer_htmlwriter_SRCS
@@ -301,6 +333,7 @@
   Stl_Util
   CSSHelperBase
   MessagePart
+  Enums
   REQUIRED_HEADERS MessageViewer_viewer_HEADERS
   PREFIX MessageViewer
   RELATIVE viewer
@@ -330,6 +363,7 @@
   MessageViewerUtil
   MarkMessageReadHandler
   IconNameCache
+  MimeType
   REQUIRED_HEADERS MessageViewer_utils_HEADERS
   PREFIX MessageViewer
   RELATIVE utils
@@ -503,3 +537,44 @@
 install(FILES notify/messageviewer.notifyrc DESTINATION ${KDE_INSTALL_KNOTIFY5RCDIR} )
 install(FILES scamdetection/data/longurlServices.json DESTINATION ${KDE_INSTALL_DATADIR}/messageviewer )
 
+Project(Otp)
+
+set(libotp_SRCS
+  ${libmessageviewer_otp_SRCS}
+  ${libmessageviewer_otp_extra_SRCS}
+  settings/messageviewersettings.cpp
+)
+ecm_qt_declare_logging_category(libotp_SRCS HEADER messageviewer_debug.h IDENTIFIER MESSAGEVIEWER_LOG CATEGORY_NAME log_messageviewer)
+
+kconfig_add_kcfg_files(libotp_SRCS
+  settings/globalsettings_messageviewer.kcfgc
+)
+
+add_library(KF5Otp
+  ${libotp_SRCS}
+)
+generate_export_header(KF5Otp BASE_NAME otp)
+add_library(KF5::Otp ALIAS KF5Otp)
+
+target_link_libraries(KF5Otp
+PUBLIC
+  KF5::MessageCore #NodeHelper, StringUtils, Settings
+  KF5::PimCommon #AttachmentTemporaryFile handling
+  KF5::Libkleo
+PRIVATE
+  KF5::Mime
+  KF5::IconThemes
+  ${libmessageviewer_web_LIB}
+  Grantlee5::TextDocument
+)
+
+install(TARGETS
+    KF5Otp
+    EXPORT KF5OtpTargets ${KF5_INSTALL_TARGETS_DEFAULT_ARGS} ${LIBRARY_NAMELINK}
+)
+
+set_target_properties(KF5Otp PROPERTIES
+    VERSION ${MESSAGEVIEWER_VERSION_STRING}
+    SOVERSION ${MESSAGEVIEWER_SOVERSION}
+    EXPORT_NAME Otp
+)