diff --git a/clang18.spec b/clang18.spec
index 5646375..bec0457 100644
--- a/clang18.spec
+++ b/clang18.spec
@@ -183,6 +183,10 @@ BuildRequires: perl(Sys::Hostname)
 
 Requires:	%{name}-libs%{?_isa} = %{version}-%{release}
 
+%if %{with compat_build}
+Conflicts: clang = %{maj_ver}
+%endif
+
 # clang requires gcc, clang++ requires libstdc++-devel
 # - https://bugzilla.redhat.com/show_bug.cgi?id=1021645
 # - https://bugzilla.redhat.com/show_bug.cgi?id=1158594
@@ -217,6 +221,9 @@ Recommends: libatomic%{?_isa}
 # with -fopenmp.
 Recommends: libomp-devel%{sub_pkg_suffix}%{_isa} = %{version}
 Recommends: libomp%{sub_pkg_suffix}%{_isa} = %{version}
+%if %{with compat_build}
+Conflicts: clang-libs = %{maj_ver}
+%endif
 
 %description libs
 Runtime library for clang.