diff --git a/MANIFEST.in b/MANIFEST.in
index f731431a..b444026c 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -1,2 +1,3 @@
 include ms2pip/cython_modules/*.c
 include ms2pip/models/*/*.c
+include ms2pip/models/*.h
diff --git a/pyproject.toml b/pyproject.toml
index 0b2f0c52..effcaf0e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,2 +1,3 @@
 [build-system]
 requires = ["setuptools", "cython", "numpy"]
+build-backend = "setuptools.build_meta"