diff --git a/kf5-ktnef.spec b/kf5-ktnef.spec
index 98019af..a3b2e54 100644
--- a/kf5-ktnef.spec
+++ b/kf5-ktnef.spec
@@ -23,6 +23,11 @@ URL:     https://cgit.kde.org/%{framework}.git
 %endif
 Source0:        http://download.kde.org/%{stable}/applications/%{version}/src/%{framework}-%{version}.tar.xz
 
+# libical (and thus kcalendarcore) not on all arches for RHEL8.
+%if 0%{?rhel} == 8
+ExclusiveArch: x86_64 ppc64le %{arm}
+%endif
+
 BuildRequires:  extra-cmake-modules
 BuildRequires:  kf5-rpm-macros
 BuildRequires:  kf5-kdelibs4support-devel >= 5.15