diff --git a/build.spec.inc b/build.spec.inc
index 39814fa..ea72efb 100644
--- a/build.spec.inc
+++ b/build.spec.inc
@@ -230,3 +230,23 @@ popd
 %cmake_build --target runtimes
 
 cd ..
+
+%if %{with bundle_compat_lib}
+%cmake -S ../llvm-project-%{compat_ver}.src/llvm -B ../llvm-compat-libs -G Ninja \
+    -DCMAKE_INSTALL_PREFIX=%{buildroot}%{_libdir}/llvm%{compat_maj_ver}/ \
+    -DCMAKE_SKIP_RPATH=ON \
+    -DCMAKE_BUILD_TYPE=Release \
+    -DBUILD_SHARED_LIBS=OFF \
+    -DLLVM_BUILD_LLVM_DYLIB=ON \
+    -DLLVM_ENABLE_EH=ON \
+    -DLLVM_ENABLE_RTTI=ON \
+    -DLLVM_ENABLE_PROJECTS=clang \
+    -DLLVM_TARGETS_TO_BUILD=%{targets_to_build} \
+    -DLLVM_INCLUDE_BENCHMARKS=OFF \
+    -DLLVM_INCLUDE_TESTS=OFF
+
+%ninja_build -C ../llvm-compat-libs LLVM
+%ninja_build -C ../llvm-compat-libs libclang.so
+%ninja_build -C ../llvm-compat-libs libclang-cpp.so
+
+%endif
diff --git a/files.spec.inc b/files.spec.inc
index f8ddaa4..d00fc1c 100644
--- a/files.spec.inc
+++ b/files.spec.inc
@@ -271,6 +271,9 @@
 %if %{with compat_build}
 %config(noreplace) /etc/ld.so.conf.d/%{name}-%{_arch}.conf
 %endif
+%if %{with bundle_compat_lib}
+%{_libdir}/libLLVM.so.%{compat_maj_ver}*
+%endif
 
 %files -n %{pkg_name_llvm}-devel
 %license llvm/LICENSE.TXT
@@ -364,8 +367,12 @@
 %files -n %{pkg_name_clang}-libs
 %license clang/LICENSE.TXT
 %{_prefix}/lib/clang/%{maj_ver}/include/*
-%{install_libdir}/libclang.so.*
-%{install_libdir}/libclang-cpp.so.*
+%{install_libdir}/libclang.so.%{maj_ver}*
+%{install_libdir}/libclang-cpp.so.%{maj_ver}*
+%if %{with bundle_compat_lib}
+%{_libdir}/libclang.so.%{compat_maj_ver}*
+%{_libdir}/libclang-cpp.so.%{compat_maj_ver}*
+%endif
 
 %files -n %{pkg_name_clang}-devel
 %license clang/LICENSE.TXT
diff --git a/globals.spec.inc b/globals.spec.inc
index 5714776..4b8cb30 100644
--- a/globals.spec.inc
+++ b/globals.spec.inc
@@ -5,9 +5,20 @@
 %else
   %bcond_with gold
 %endif
+
+# Build compat packages llvmN instead of main package for the current LLVM
+# version. Used on Fedora.
 %bcond_with compat_build
+# Bundle compat libraries for a previous LLVM version, as part of llvm-libs and
+# clang-libs. Used on RHEL.
+%bcond_with bundle_compat_lib
 %bcond_without check
 
+%if %{with bundle_compat_lib}
+%global compat_maj_ver 18
+%global compat_ver %{compat_maj_ver}.1.8
+%endif
+
 # Compat builds do not include python-lit and lldb
 %if %{with compat_build}
 %bcond_with python_lit
diff --git a/install.spec.inc b/install.spec.inc
index 552e531..204781b 100644
--- a/install.spec.inc
+++ b/install.spec.inc
@@ -269,3 +269,8 @@ rm %{buildroot}%{_bindir}/llvm-config%{exec_suffix}
 # ghost presence
 touch %{buildroot}%{_bindir}/llvm-config%{exec_suffix}
 
+%if %{with bundle_compat_lib}
+install -m 0755 ../llvm-compat-libs/lib/libLLVM.so.%{compat_maj_ver}* %{buildroot}%{_libdir}
+install -m 0755 ../llvm-compat-libs/lib/libclang.so.%{compat_maj_ver}* %{buildroot}%{_libdir}
+install -m 0755 ../llvm-compat-libs/lib/libclang-cpp.so.%{compat_maj_ver}* %{buildroot}%{_libdir}
+%endif
diff --git a/prep.spec.inc b/prep.spec.inc
index 896a4c4..aacb9c3 100644
--- a/prep.spec.inc
+++ b/prep.spec.inc
@@ -3,6 +3,11 @@
 %{gpgverify} --keyring='%{SOURCE6}' --signature='%{SOURCE1}' --data='%{SOURCE0}'
 %endif
 
+%if %{with bundle_compat_lib}
+%{gpgverify} --keyring='%{SOURCE6}' --signature='%{SOURCE3001}' --data='%{SOURCE3000}'
+%setup -T -q -b 3000 -n llvm-project-%{compat_ver}.src
+%endif
+
 # -T     : Do Not Perform Default Archive Unpacking (without this, the <n>th source would be unpacked twice)
 # -b <n> : Unpack The nth Sources Before Changing Directory
 # -n     : Set Name of Build Directory