diff --git a/libdap.spec b/libdap.spec
index ffb88af..36409ba 100644
--- a/libdap.spec
+++ b/libdap.spec
@@ -1,7 +1,7 @@
 Name: libdap
 Summary: The C++ DAP2 library from OPeNDAP
 Version: 3.18.3
-Release: 5.0.riscv64%{?dist}
+Release: 5.1.riscv64%{?dist}
 
 License: LGPLv2+
 Group: Development/Libraries
@@ -9,6 +9,9 @@ URL: http://www.opendap.org/
 Source0: http://www.opendap.org/pub/source/libdap-%{version}.tar.gz
 #Don't run HTTP tests - builders don't have network connections
 Patch0: libdap-offline.patch
+# glibc all xdr_* symbols are now version (i.e. in compatibility mode)
+# we need to use newer, external library
+Patch1: libdap-use-libtirpc.patch
 
 # For autoreconf
 BuildRequires: libtool
@@ -22,6 +25,7 @@ BuildRequires: libuuid-devel
 BuildRequires: libxml2-devel
 BuildRequires: openssl-devel
 BuildRequires: pkgconfig
+BuildRequires: libtirpc-devel
 %ifarch %{valgrind_arches}
 BuildRequires: valgrind
 %endif
@@ -43,6 +47,7 @@ Group: Development/Libraries
 Requires: %{name} = %{version}-%{release}
 Requires: curl-devel
 Requires: libxml2-devel
+Requires: libtirpc-devel
 Requires: pkgconfig
 # for the /usr/share/aclocal directory ownership
 Requires: automake
@@ -63,6 +68,7 @@ Documentation of the libdap library.
 %prep
 %setup -q -n %{name}-%{version}
 %patch0 -p1 -b .offline
+%patch1 -p1 -b .tirpc
 iconv -f latin1 -t utf8 < COPYRIGHT_W3C > COPYRIGHT_W3C.utf8
 touch -r COPYRIGHT_W3C COPYRIGHT_W3C.utf8
 mv COPYRIGHT_W3C.utf8 COPYRIGHT_W3C
@@ -131,6 +137,9 @@ make check
 
 
 %changelog
+* Mon Jun 18 2018 David Abdurachmanov <david.abdurachmanov@gmail.com> - 3.18.3-5.1.riscv64
+- Use libtirpc library for xdr_*
+
 * Tue Jun 05 2018 David Abdurachmanov <david.abdurachmanov@gmail.com> - 3.18.3-5.0.riscv64
 - Switch to use %{valgrind_arches}