diff --git a/soprano.spec b/soprano.spec
index b03e176..329b6d7 100644
--- a/soprano.spec
+++ b/soprano.spec
@@ -3,7 +3,7 @@
 
 Name:          soprano
 Version:       2.9.4
-Release:       4mamba
+Release:       5mamba
 Epoch:         1
 Summary:       The QT/C++ RDF framework
 Group:         Applications/Development
@@ -55,13 +55,15 @@ This package contains dynamic libraries provided by %{name}.
 Group:         Development/Libraries
 Summary:       Static libraries and headers for %{name}
 Requires:      %{name} = %{?epoch:%epoch:}%{version}-%{release}
-Obsoletes:     soprano-devel
+Obsoletes:     soprano-devel < 1:2.9.4-5mamba
 Provides:      soprano-devel = %{?epoch:%epoch:}%{version}-%{release}
 Requires:      %{name}-backend-redland = %{?epoch:%epoch:}%{version}-%{release}
-%ifnarch arm
-Requires:      %{name}-backend-sesame2 = %{?epoch:%epoch:}%{version}-%{release}
-%endif
-Requires:      %{name}-backend-virtuoso = %{?epoch:%epoch:}%{version}-%{release}
+#%ifnarch arm
+#Requires:      %{name}-backend-sesame2 = %{?epoch:%epoch:}%{version}-%{release}
+#%endif
+#%ifarch x86_64 aarch64
+#Requires:      %{name}-backend-virtuoso = %{?epoch:%epoch:}%{version}-%{release}
+#%endif
 
 %description -n %{libname}-devel
 Soprano (formally known as QRDF) is a library which provides a QT wrapper API to different RDF storage solutions.
@@ -74,6 +76,9 @@ Summary:       Redland backend for %{name}
 Provides:      %{name}-backend = %{?epoch:%epoch:}%{version}-%{release}
 Provides:      sopranobackend
 Requires:      %{libname} = %{?epoch:%epoch:}%{version}-%{release}
+%ifnarch x86_64 aarch64
+Obsoletes:     soprano-backend-virtuoso < 1:2.9.4-5mamba
+%endif
 
 %description backend-redland
 This package provides the Redland storage backend for %{name}.
@@ -122,7 +127,10 @@ JAVA_HOME=%{_jvmdir}/jdk
 QTDIR=%{_qt4_prefix}; export QTDIR
 PATH="%{_qt4_bindir}:%{_kdebindir}:/bin:/usr/bin"; export PATH
 %cmake -d build \
-  -DSOPRANO_BUILD_API_DOCS:BOOL=%{!?build_apidocs:0}%{?build_apidocs}
+  -DSOPRANO_BUILD_API_DOCS:BOOL=%{!?build_apidocs:0}%{?build_apidocs} \
+%ifnarch x86_64 aarch64
+  -DSOPRANO_DISABLE_VIRTUOSO_BACKEND=TRUE
+%endif
 
 %install
 [ "%{buildroot}" != / ] && rm -rf "%{buildroot}"
@@ -147,6 +155,7 @@ PATH="%{_qt4_bindir}:%{_kdebindir}:/bin:/usr/bin"; export PATH
 %{_datadir}/soprano/plugins/*parser.desktop
 %{_datadir}/soprano/plugins/*serializer.desktop
 %{_datadir}/soprano/rules/*
+%doc AUTHORS COPYING.LIB README TODO
 
 %files -n %{libname}
 %defattr(-,root,root)
@@ -156,7 +165,6 @@ PATH="%{_qt4_bindir}:%{_kdebindir}:/bin:/usr/bin"; export PATH
 %{_libdir}/libsoprano.so.*
 %{_libdir}/soprano/libsoprano_*parser.so
 %{_libdir}/soprano/libsoprano_*serializer.so
-%doc AUTHORS COPYING.LIB
 
 %files -n %{libname}-devel
 %defattr(-,root,root)
@@ -171,7 +179,6 @@ PATH="%{_qt4_bindir}:%{_kdebindir}:/bin:/usr/bin"; export PATH
 %{_libdir}/pkgconfig/sopranoindex.pc
 %{_libdir}/pkgconfig/sopranoserver.pc
 %{_datadir}/soprano/cmake/SopranoAddOntology.cmake
-%doc README TODO
 
 %files backend-redland
 %defattr(-,root,root,-)
@@ -189,10 +196,12 @@ PATH="%{_qt4_bindir}:%{_kdebindir}:/bin:/usr/bin"; export PATH
 %endif
 %endif
 
+%ifarch x86_64 aarch64
 %files backend-virtuoso
 %defattr(-,root,root,-)
 %{_libdir}/soprano/libsoprano_virtuosobackend.so
 %{_datadir}/soprano/plugins/virtuosobackend.desktop
+%endif
 
 %if %build_apidocs
 %files apidocs
@@ -201,6 +210,9 @@ PATH="%{_qt4_bindir}:%{_kdebindir}:/bin:/usr/bin"; export PATH
 %endif
 
 %changelog
+* Mon Sep 04 2023 Silvan Calarco <silvan.calarco@mambasoft.it> 2.9.4-5mamba
+- disable virtuoso backend on 32 bit plaforms
+
 * Sun Sep 03 2023 Silvan Calarco <silvan.calarco@mambasoft.it> 2.9.4-4mamba
 - rebuilt