diff --git a/spack-0.16.2.tar.gz b/spack-0.16.2.tar.gz
deleted file mode 100644
index d2b4d02..0000000
--- a/spack-0.16.2.tar.gz
+++ /dev/null
@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:ed3e5d479732b0ba82489435b4e0f9088571604e789f7ab9bc5ce89030793350
-size 5541562
diff --git a/spack-0.16.3.tar.gz b/spack-0.16.3.tar.gz
new file mode 100644
index 0000000..36675ed
--- /dev/null
+++ b/spack-0.16.3.tar.gz
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:26636a2e2cc066184f12651ac6949f978fc041990dba73934960a4c9c1ea383d
+size 5543891
diff --git a/spack.changes b/spack.changes
index 0e4777d..82f7823 100644
--- a/spack.changes
+++ b/spack.changes
@@ -1,3 +1,18 @@
+-------------------------------------------------------------------
+Fri Oct  1 05:55:10 UTC 2021 - Egbert Eich <eich@suse.com>
+
+- Utilize sysuser infrastructure to set group spack. 
+
+-------------------------------------------------------------------
+Wed Sep 29 20:32:58 UTC 2021 - Antoine Ginies <aginies@suse.com>
+
+- update to version 0.16.3 (JSC#SLE-22137):
+  * clang/llvm: fix version detection
+  * Fix use of quotes in Python build system
+  * Ensure all roots of an installed environment are marked explicit in db
+  * Fix fetching for Python 3.8 and 3.9
+  * locks: only open lockfiles once instead of for every lock held
+
 -------------------------------------------------------------------
 Fri Aug  6 14:28:20 UTC 2021 - Christian Goll <cgoll@suse.com>
 
@@ -21,7 +36,7 @@ Tue Jul  6 21:45:21 UTC 2021 - Egbert Eich <eich@suse.com>
 -------------------------------------------------------------------
 Wed Jun  2 14:04:26 UTC 2021 - Antoine Ginies <aginies@suse.com>
 
-- fix typo to export prefix in patch:
+- fix typo to export prefix in patch (bsc#1191395):
   Adapt-shell-scripts-that-set-up-the-environment-for-different-shells.patch
 
 -------------------------------------------------------------------
diff --git a/spack.spec b/spack.spec
index f905cdb..7fa09d2 100644
--- a/spack.spec
+++ b/spack.spec
@@ -36,7 +36,7 @@ ExclusiveArch:  do_not_build
 # non oss packages
 %define spack_trigger_external cuda-nvcc
 Name:           spack
-Version:        0.16.2
+Version:        0.16.3
 Release:        0
 Summary:        Package manager for HPC systems
 License:        Apache-2.0 AND MIT AND Python-2.0 AND BSD-3-Clause
@@ -63,6 +63,7 @@ BuildRequires:  polkit
 BuildRequires:  python-base
 BuildRequires:  python3-urllib3
 BuildRequires:  sudo
+BuildRequires:  sysuser-tools
 Requires:       %{name}-recipes = %{version}
 Requires:       bzip2
 Requires:       curl
@@ -352,6 +353,11 @@ ln -sf %{_localstatedir}/cache/spack %{buildroot}%{_localstatedir}/lib/spack/cac
 # Remove problematic binaries which are removed upstream with
 # 0889be20e0d9dcdf4346cdeaa0647285187375f3
 rm -r %{buildroot}%{_localstatedir}/lib/spack/repos/builtin/packages/patchelf/test/
+
+echo "g %{name} -" > system-user-%{name}.conf
+%sysusers_generate_pre system-user-%{name}.conf %{name} system-user-%{name}.conf
+install -D -m 644 system-user-%{name}.conf %{buildroot}%{_sysusersdir}/system-user-%{name}.conf
+
 %fdupes %{buildroot}%{spack_dir}
 %fdupes %{buildroot}%{_datarootdir}/spack
 %fdupes %{buildroot}%{_localstatedir}/lib/spack
@@ -364,8 +370,7 @@ cp -r texinfo/Spack.info.gz %{buildroot}%{_infodir}
 [ -d texinfo/Spack-figures ] && cp -r texinfo/Spack-figures %{buildroot}%{_infodir}
 %endif
 
-%pre
-getent group %spack_group >/dev/null || groupadd -r %spack_group
+%pre -f %{name}.pre
 
 %post
 # Replace /etc/spack/compilers.yaml
@@ -419,6 +424,7 @@ sed -i "s@HOSTTYPE@$HOSTTYPE@" %{spack_dir}/etc/spack/compilers.yaml
 %dir %{_sysconfdir}/skel/.spack
 %config %{_sysconfdir}/skel/.spack/config.yaml
 # repos directory is installed in -recipes
+%{_sysusersdir}/system-user-%{name}.conf
 %exclude %{_localstatedir}/lib/spack/repos
 
 %files recipes