diff --git a/Compiler/clhep/build b/Compiler/clhep/build
index 91eb599..6e021f3 100755
--- a/Compiler/clhep/build
+++ b/Compiler/clhep/build
@@ -1,20 +1,2 @@
 #!/usr/bin/env modbuild
 
-pbuild::set_download_url "https://proj-clhep.web.cern.ch/proj-clhep/dist1/$P-${V_PKG}.tgz"
-pbuild::add_to_group 'Compiler'
-
-pbuild::install_docfiles 'ChangeLog'
-pbuild::install_docfiles 'compilers.txt'
-pbuild::install_docfiles 'COPYING'
-pbuild::install_docfiles 'COPYING.LESSER'
-pbuild::install_docfiles 'README.md'
-
-pbuild::post_prep() {
-	mv CLHEP/* .
-}
-
-# Local Variables:
-# mode: sh
-# sh-basic-offset: 8
-# tab-width: 8
-# End:
diff --git a/Compiler/clhep/files/config.yaml b/Compiler/clhep/files/config.yaml
new file mode 100644
index 0000000..7f13923
--- /dev/null
+++ b/Compiler/clhep/files/config.yaml
@@ -0,0 +1,23 @@
+---
+# yamllint disable rule:line-length
+format: 1
+clhep:
+  defaults:
+    group: Compiler
+    overlay: base
+    systems: [rhel7, rhel8, rhel9]
+    docfiles: [AUTHORS, LICENSE, NEWS, README]
+    configure_with: cmake
+    build_requires: ['cmake/3.26.3']
+    urls:
+      - url: https://proj-clhep.web.cern.ch/proj-clhep/dist1/clhep-2.4.7.1.tgz
+  shasums:
+    clhep-2.4.7.1.tgz: 1c8304a7772ac6b99195f1300378c6e3ddf4ad07c85d64a04505652abb8a55f9
+
+  versions:
+    2.4.7.1:
+      variants:
+        - systems: [merlin-*, ra-*]
+          group_deps:
+            compiler: {gcc: [13.1.0]}
+          relstage: unstable
diff --git a/Compiler/geant4/build b/Compiler/geant4/build
index b381e4a..6e021f3 100755
--- a/Compiler/geant4/build
+++ b/Compiler/geant4/build
@@ -1,27 +1,2 @@
 #!/usr/bin/env modbuild
 
-declare -r VERSION=${V_MAJOR}.$(printf '%02d' ${V_MINOR})
-pbuild::set_download_url "http://cern.ch/geant4-data/releases/$P.${VERSION}.tar.gz"
-pbuild::add_to_group 'Compiler'
-
-#pbuild::install_docfiles 'ChangeLog'
-#pbuild::install_docfiles 'compilers.txt'
-#pbuild::install_docfiles 'COPYING'
-#pbuild::install_docfiles 'COPYING.LESSER'
-#pbuild::install_docfiles 'README.md'
-
-pbuild::pre_configure() {
-	pbuild::add_configure_args "-DCMAKE_INSTALL_PREFIX=${PREFIX}"
-	pbuild::add_configure_args "-DGEANT4_USE_SYSTEM_CLHEP=ON"
-	pbuild::add_configure_args "-DPC_EXPAT_INCLUDE_DIRS=${LIBEXPAT_INCLUDE_DIR}"
-	pbuild::add_configure_args "-DGEANT4_INSTALL_DATA=ON"
-	if pbuild::use_flag 'multithreaded'; then
-		pbuild::add_configure_args "-DGEANT4_BUILD_MULTITHREADED=ON"
-	fi
-}
-
-# Local Variables:
-# mode: sh
-# sh-basic-offset: 8
-# tab-width: 8
-# End:
diff --git a/Compiler/geant4/files/config.yaml b/Compiler/geant4/files/config.yaml
new file mode 100644
index 0000000..d4f4e5e
--- /dev/null
+++ b/Compiler/geant4/files/config.yaml
@@ -0,0 +1,28 @@
+---
+# yamllint disable rule:line-length
+format: 1
+geant4:
+  defaults:
+    group: Compiler
+    overlay: base
+    systems: [rhel7, rhel8, rhel9]
+    docfiles: [AUTHORS, LICENSE, NEWS, README]
+    configure_with: cmake
+    urls:
+      - url: https://gitlab.cern.ch/geant4/geant4/-/archive/v11.2.1/geant4-v11.2.1.tar.gz
+  shasums:
+    geant4-v11.2.1.tar.gz: 76c9093b01128ee2b45a6f4020a1bcb64d2a8141386dea4674b5ae28bcd23293
+
+  versions:
+    v11.2.1:
+      variants:
+        - systems: [merlin-*, ra-*]
+          group_deps:
+            compiler: {gcc: [13.1.0]}
+          build_requires: ['clhep/2.4.7.1', 'libexpat/2.2.6','cmake/3.26.3']
+          configure_args: ['-DGEANT4_USE_SYSTEM_CLHEP=ON',
+            '-DPC_EXPAT_INCLUDE_DIRS=${LIBEXPAT_INCLUDE_DIR}',
+            '-DGEANT4_INSTALL_DATA=ON',
+            '-DGEANT4_BUILD_MULTITHREADED=ON']
+          relstage: unstable
+