diff --git a/sources b/sources
index 2285c8a..820be91 100644
--- a/sources
+++ b/sources
@@ -1,2 +1,2 @@
-SHA512 (xtide-2.15.5.tar.xz) = 314c3d256a873ae5862e83050937c72983e5ac0bc9dc2c1a9264d0285f73f681eae1451706c5c6c2829d980423044e83adff3fcf8975b33eb03eed8cb72f1f43
-SHA512 (harmonics-dwf-20240104-free.tar.xz) = 85f0b2cd49ebea18e96523a9df3eac0025bbfea0546ab43ca36cc6535ab786d51cd2d4693a95145770fb72ad2a4f39a850d5455e0e6bfd21649eaba5868683c0
+SHA512 (xtide-2.15.6.tar.xz) = cd24908a9f4541ab2b19444dba54aab92310e49d2ba0321d9bbcde9806d7cc975828cc5f22fe0a1a73cebf96f4ad1ccd1530c016e8b22f7d54675aeff9528c82
+SHA512 (harmonics-dwf-20251228-free.tar.xz) = d7710c2f0fcaf32ca8e017f073912db5e4d344dbc1710c2709766232d0c77d08b4cec65418f9c7196bb792271f0136a8a9fb59de021e8d4c0ad66c2c558ae87b
diff --git a/xtide.spec b/xtide.spec
index 4f27084..41061d0 100644
--- a/xtide.spec
+++ b/xtide.spec
@@ -1,12 +1,18 @@
-%define          mainver   2.15.5
+%define          mainver   2.15.6
 #%%define          betatag   dev-20160114
-%define          dwfdate   20240104
+%define          dwfdate   20251228
 
 %define          baserelease 4
 
 
 %define          rel        %{?betatag:0.}%{baserelease}%{?betatag:.%(echo %betatag | sed -e 's|-||g')}
 
+%if 0%{?fedora} >= 42
+%global          use_systemd_sysusers  1
+%else
+# Drop this when F41 gets EOF
+%global          use_systemd_sysusers  0
+%endif
 
 Summary:         Calculate tide all over the world
 Name:            xtide
@@ -30,7 +36,8 @@ Source30:        xtide-README.fedora
 #Source41:        harmonics-dwf-%%{dwfdate}-dump-US.tar.bz2
 Source42:        https://flaterco.com/files/xtide/harmonics-dwf-%{dwfdate}-free.tar.xz
 
-License:         GPLv3+
+# Automatically converted from old format: GPLv3+ - review is highly recommended.
+License:         GPL-3.0-or-later
 
 BuildRequires:   make
 BuildRequires:   gcc-c++
@@ -59,24 +66,29 @@ Requires:        xorg-x11-fonts-misc
 Requires:        xtide-common = %{version}-%{release}
 Requires:        libxtide%{?_isa} = %{version}-%{release}
 
+%if ! %{use_systemd_sysusers}
 Requires(pre):      shadow-utils
+%endif
 Requires(preun):    systemd
 Requires(postun):   systemd
 Requires(post):     systemd
 
 %package -n      libxtide
 Summary:         XTide library
-License:         GPLv3+
+# Automatically converted from old format: GPLv3+ - review is highly recommended.
+License:         GPL-3.0-or-later
 
 %package -n      libxtide-devel
 Summary:         Development files for libxtide
-License:         GPLv3+
+# Automatically converted from old format: GPLv3+ - review is highly recommended.
+License:         GPL-3.0-or-later
 Requires:        libxtide%{?_isa} = %{version}-%{release}
 
 
 %package         common
 Summary:         Xtide common files
-License:         Public Domain
+# Automatically converted from old format: Public Domain - needs further work
+License:         LicenseRef-Callaway-Public-Domain
 Requires:        bzip2
 Requires:        wget
 BuildArch:       noarch
@@ -160,6 +172,13 @@ sed -i.rpath ltmain.sh \
 	-e 's|\$finalize_rpath|\$finalize_no_rpath|' \
 	%{nil}
 
+%if %{use_systemd_sysusers}
+# Create a sysusers.d config file
+cat >xtide.sysusers.conf <<EOF
+u xttpd - 'XTide web server' %{_sysconfdir}/%{name} -
+EOF
+%endif
+
 %build
 %configure \
    --enable-systemd \
@@ -264,6 +283,10 @@ cp -a harmonics-dwf-%{dwfdate}/[A-Z]* \
 # 3 cleanup
 rm -rf $RPM_BUILD_ROOT%{_libdir}/libxtide.{a,la}
 
+%if %{use_systemd_sysusers}
+install -m0644 -D xtide.sysusers.conf %{buildroot}%{_sysusersdir}/xtide.conf
+%endif
+
 %post
 %systemd_post xttpd.socket xttpd.service
 exit 0
@@ -274,6 +297,7 @@ exit 0
 
 
 %pre
+%if ! %{use_systemd_sysusers}
 getent group xttpd &>/dev/null || \
    %{_sbindir}/groupadd -r xttpd
 getent passwd xttpd &> /dev/null || \
@@ -284,6 +308,7 @@ getent passwd xttpd &> /dev/null || \
    -r \
    -s /sbin/nologin \
    xttpd 2>/dev/null
+%endif
 exit 0
 
 %preun
@@ -335,8 +360,47 @@ exit 0
 
 %{_sbindir}/xttpd
 %{_datadir}/man/man8/xttpd.8*
+%if %{use_systemd_sysusers}
+%{_sysusersdir}/xtide.conf
+%endif
 
 %changelog
+* Wed Jan 14 2026 Jitka Plesnikova <jplesnik@redhat.com> - 2.15.6-4
+- Rebuild for new gpsd
+
+* Mon Dec 29 2025 Mamoru TASAKA <mtasaka@fedoraproject.org> - 2.15.6-3
+- Update harmonics data to 20251228
+
+* Fri Jul 25 2025 Fedora Release Engineering <releng@fedoraproject.org> - 2.15.6-2
+- Rebuilt for https://fedoraproject.org/wiki/Fedora_43_Mass_Rebuild
+
+* Sun Jun 29 2025 Mamoru TASAKA <mtasaka@fedoraproject.org> - 2.15.6-1
+- 2.15.6
+
+* Tue May 27 2025 Remi Collet <remi@fedoraproject.org> - 2.15.5-11
+- rebuild for new gpsd
+
+* Thu Feb 13 2025 Mamoru TASAKA <mtasaka@fedoraproject.org> - 2.15.5-10
+- Only apply Systemd Sysusers.d usage for F-42+
+
+* Tue Feb 11 2025 Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> - 2.15.5-10
+- Add sysusers.d config file to allow rpm to create users/groups automatically
+
+* Sun Jan 19 2025 Fedora Release Engineering <releng@fedoraproject.org> - 2.15.5-9
+- Rebuilt for https://fedoraproject.org/wiki/Fedora_42_Mass_Rebuild
+
+* Mon Dec 30 2024 Mamoru TASAKA <mtasaka@fedoraproject.org> - 2.15.5-8
+- Update harmonics data to 20241229
+
+* Thu Jul  25 2024 Miroslav Suchý <msuchy@redhat.com> - 2.15.5-7
+- convert license to SPDX
+
+* Sat Jul 20 2024 Fedora Release Engineering <releng@fedoraproject.org> - 2.15.5-6
+- Rebuilt for https://fedoraproject.org/wiki/Fedora_41_Mass_Rebuild
+
+* Sat Jan 27 2024 Fedora Release Engineering <releng@fedoraproject.org> - 2.15.5-5
+- Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild
+
 * Sat Jan  6 2024 Mamoru TASAKA <mtasaka@fedoraproject.org> - 2.15.5-4
 - harmonics data update (20240104)