diff --git a/CMakeLists.txt b/CMakeLists.txt
index d67984af..52296781 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -45,9 +45,4 @@ add_subdirectory(src/callback)
 
 xo_export_cmake_config(${PROJECT_NAME} ${PROJECT_VERSION} ${PROJECT_NAME}Targets)
 
-# ----------------------------------------------------------------
-# install .hpp files
-
-xo_install_include_tree()
-
 # end CMakeLists.txt
diff --git a/src/callback/CMakeLists.txt b/src/callback/CMakeLists.txt
index 114a89e2..cfeaf08c 100644
--- a/src/callback/CMakeLists.txt
+++ b/src/callback/CMakeLists.txt
@@ -4,7 +4,7 @@ set(SELF_LIB callback)
 #set(SELF_SRCS CallbackSet.cpp)
 
 xo_add_headeronly_library(${SELF_LIB})
-xo_install_library3(${SELF_LIB} ${PROJECT_NAME}Targets)
+xo_install_library4(${SELF_LIB} ${PROJECT_NAME}Targets)
 
 # ----------------------------------------------------------------
 # external dependencies: