diff --git a/rnp-v0.17.0-gcc13.patch b/rnp-v0.17.0-gcc13.patch
deleted file mode 100644
index e647c11..0000000
--- a/rnp-v0.17.0-gcc13.patch
+++ /dev/null
@@ -1,21 +0,0 @@
-From e665f81ef9568ac5dd4411d6814c75c06262b91c Mon Sep 17 00:00:00 2001
-From: Joonas Niilola <juippis@gentoo.org>
-Date: Wed, 3 May 2023 10:31:07 +0300
-Subject: [PATCH] include/sexp/sexp-error.h: fix missing cstdint include
-
----
- include/sexp/sexp-error.h | 1 +
- 1 file changed, 1 insertion(+)
-
-Index: rnp-v0.17.0/src/libsexp/include/sexp/sexp-error.h
-===================================================================
---- rnp-v0.17.0.orig/src/libsexp/include/sexp/sexp-error.h
-+++ rnp-v0.17.0/src/libsexp/include/sexp/sexp-error.h
-@@ -29,6 +29,7 @@
- 
- #pragma once
- 
-+#include <cstdint>
- #include <exception>
- #include <iostream>
- #include <string>
diff --git a/rnp-v0.17.0-system-sexp.patch b/rnp-v0.17.0-system-sexp.patch
new file mode 100644
index 0000000..daf1776
--- /dev/null
+++ b/rnp-v0.17.0-system-sexp.patch
@@ -0,0 +1,17 @@
+Index: rnp-v0.17.0/CMakeLists.txt
+===================================================================
+--- rnp-v0.17.0.orig/CMakeLists.txt
++++ rnp-v0.17.0/CMakeLists.txt
+@@ -176,10 +176,8 @@ if (ENABLE_FUZZERS)
+ endif()
+ add_subdirectory(src/common)
+ 
+-set(WITH_SEXP_CLI OFF)
+-set(WITH_SEXP_TESTS OFF)
+-set(CMAKE_INSTALL_DEFAULT_COMPONENT_NAME development)
+-add_subdirectory(src/libsexp EXCLUDE_FROM_ALL)
++find_package(PkgConfig REQUIRED)
++pkg_check_modules(SEXP REQUIRED sexp)
+ 
+ add_subdirectory(src/lib)
+ add_subdirectory(src/rnp)
diff --git a/rnp.changes b/rnp.changes
index df2826f..3f3fd5b 100644
--- a/rnp.changes
+++ b/rnp.changes
@@ -1,3 +1,15 @@
+-------------------------------------------------------------------
+Wed Jun 14 21:01:38 UTC 2023 - Andreas Stieger <Andreas.Stieger@gmx.de>
+
+- build with system sexp library
+  (add rnp-v0.17.0-system-sexp.patch)
+- drop rnp-v0.17.0-gcc13.patch no longer needed
+
+-------------------------------------------------------------------
+Wed Jun 14 20:57:32 UTC 2023 - Andreas Stieger <Andreas.Stieger@gmx.de>
+
+- fix build on Leap (json-c)
+
 -------------------------------------------------------------------
 Mon Jun 12 20:32:19 UTC 2023 - Andreas Stieger <Andreas.Stieger@gmx.de>
 
diff --git a/rnp.spec b/rnp.spec
index 1b0a4bb..f39709e 100644
--- a/rnp.spec
+++ b/rnp.spec
@@ -28,15 +28,16 @@ Source:         https://github.com/rnpgp/rnp/releases/download/v%{version}/%{nam
 Source2:        https://github.com/rnpgp/rnp/releases/download/v%{version}/%{name}-v%{version}.tar.gz.asc
 Source3:        https://www.rnpgp.org/openpgp_keys/31AF5A24D861EFCB7CB79A1924900CE0AEFB5417-50DA59D5B9134FA2DB1EB20CFB829AB5D0FE017F.asc#/%{name}.keyring
 Patch0:         rnp-v0.17.0-disable-static.patch
-Patch1:         rnp-v0.17.0-gcc13.patch
+Patch2:         rnp-v0.17.0-system-sexp.patch
 BuildRequires:  cmake >= 3.18
 BuildRequires:  gcc-c++
 BuildRequires:  gpg2 >= 2.2
 BuildRequires:  gtest
 BuildRequires:  pkgconfig
-BuildRequires:  cmake(json-c) >= 0.11
 BuildRequires:  pkgconfig(botan-2) >= 2.14.0
 BuildRequires:  pkgconfig(bzip2)
+BuildRequires:  pkgconfig(json-c) >= 0.11
+BuildRequires:  pkgconfig(sexp) >= 0.8.2
 BuildRequires:  pkgconfig(zlib)
 BuildRequires:  rubygem(asciidoctor)
 
@@ -44,9 +45,7 @@ BuildRequires:  rubygem(asciidoctor)
 RNP is a set of OpenPGP (RFC4880) tools, an alternative to GnuPG.
 
 %package -n librnp%{soname}
-%global libsexp_version 0.8.2
 Summary:        OpenPGP implementation as a C++ library fully compliant with RFC 4880
-Provides:       bundled(libsexp) = %{libsexp_version}
 
 %description -n librnp%{soname}
 RNP is a set of OpenPGP (RFC4880) tools, an alternative to GnuPG.
@@ -63,15 +62,12 @@ This package contains the files needed to build against librnp.
 
 %prep
 %autosetup -p1 -n %{name}-v%{version}
-pushd src/libsexp
-cp LICENSE.md ../../LICENSE-libsexp.md
-grep -q %{libsexp_version} version.txt
-popd
+rm -rf src/libsexp
 
 %build
 %cmake \
-	-DDOWNLOAD_GTEST=off \
-	-DBUILD_TESTING=on \
+	-DDOWNLOAD_GTEST:BOOL=OFF \
+	-DBUILD_TESTING:BOOL=ON \
 	%{nil}
 %cmake_build