diff --git a/exercises/ex04_solution/heised_cpp/Makefile b/exercises/ex04_solution/heised_cpp/Makefile
index f4e2fe584b1edc27f56a1f0a3244dbac8b5fd575..f4e1f567a3d138f0a93a0ba245f0c25fa6240fcb 100644
--- a/exercises/ex04_solution/heised_cpp/Makefile
+++ b/exercises/ex04_solution/heised_cpp/Makefile
@@ -1,7 +1,7 @@
-CXX = g++
-CPPFLAGS = -std=c++14 -I${ALPSDIR}/boost -I${ALPSDIR}/alps/src
+ALPSDIR = /opt/alps/include/
 
-ALPSDIR = alps-2.2.b4-src-with-boost
+CXX = g++
+CPPFLAGS = -std=c++14 -I${ALPSDIR} -I${ALPSDIR}/boost -I${ALPSDIR}/alps/src
 
 heised:	heised.cpp
 	${CXX} ${CPPFLAGS} -o $@ $^ -llapack -lblas