diff --git a/copy-patches.sh b/copy-patches.sh
index 8edca8d..987ffe3 100755
--- a/copy-patches.sh
+++ b/copy-patches.sh
@@ -6,7 +6,7 @@ set -e
 # directory.  Use it like this:
 #   ./copy-patches.sh
 
-rhel_version=9.2
+rhel_version=9.3
 
 # Check we're in the right directory.
 if [ ! -f libnbd.spec ]; then
diff --git a/libnbd.spec b/libnbd.spec
index ca93c65..b9904d9 100644
--- a/libnbd.spec
+++ b/libnbd.spec
@@ -8,10 +8,10 @@
 %global patches_touch_autotools %{nil}
 
 # The source directory.
-%global source_directory 1.14-stable
+%global source_directory 1.15-development
 
 Name:           libnbd
-Version:        1.14.2
+Version:        1.15.12
 Release:        1%{?dist}
 Summary:        NBD client library in userspace
 
@@ -29,7 +29,7 @@ Source2:       libguestfs.keyring
 Source3:        copy-patches.sh
 
 # Patches are stored in the upstream repository:
-# https://gitlab.com/nbdkit/libnbd/-/commits/rhel-9.2/
+# https://gitlab.com/nbdkit/libnbd/-/commits/rhel-9.3/
 
 # (no patches)
 
@@ -51,6 +51,12 @@ BuildRequires:  libxml2-devel
 # For nbdfuse.
 BuildRequires:  fuse3, fuse3-devel
 
+%if !0%{?rhel}
+# For nbdublk
+BuildRequires:  liburing-devel >= 2.2
+BuildRequires:  ubdsrv-devel >= 1.0-3.rc6
+%endif
+
 # For the Python 3 bindings.
 BuildRequires:  python3-devel
 
@@ -169,6 +175,21 @@ Recommends:     fuse3
 This package contains FUSE support for %{name}.
 
 
+%if !0%{?rhel}
+%package -n nbdublk
+Summary:        Userspace NBD block device
+License:        LGPLv2+
+Requires:       %{name}%{?_isa} = %{version}-%{release}
+Recommends:     kernel >= 6.0.0
+Recommends:     %{_sbindir}/ublk
+
+
+%description -n nbdublk
+This package contains a userspace NBD block device
+based on %{name}.
+%endif
+
+
 %package bash-completion
 Summary:       Bash tab-completion for %{name}
 BuildArch:     noarch
@@ -215,6 +236,11 @@ find $RPM_BUILD_ROOT -name '*.la' -delete
 # Delete the golang man page since we're not distributing the bindings.
 rm $RPM_BUILD_ROOT%{_mandir}/man3/libnbd-golang.3*
 
+%if 0%{?rhel}
+# Delete nbdublk on RHEL.
+rm $RPM_BUILD_ROOT%{_datadir}/bash-completion/completions/nbdublk
+%endif
+
 
 %check
 function skip_test ()
@@ -318,6 +344,13 @@ make %{?_smp_mflags} check || {
 %{_mandir}/man1/nbdfuse.1*
 
 
+%if !0%{?rhel}
+%files -n nbdublk
+%{_bindir}/nbdublk
+%{_mandir}/man1/nbdublk.1*
+%endif
+
+
 %files bash-completion
 %dir %{_datadir}/bash-completion/completions
 %{_datadir}/bash-completion/completions/nbdcopy
@@ -325,9 +358,16 @@ make %{?_smp_mflags} check || {
 %{_datadir}/bash-completion/completions/nbdfuse
 %{_datadir}/bash-completion/completions/nbdinfo
 %{_datadir}/bash-completion/completions/nbdsh
+%if !0%{?rhel}
+%{_datadir}/bash-completion/completions/nbdublk
+%endif
 
 
 %changelog
+* Thu Mar 09 2023 Richard W.M. Jones <rjones@redhat.com> - 1.15.12-1
+- Rebase to 1.15.12
+  resolves: rhbz#2168628
+
 * Tue Jan 03 2023 Richard W.M. Jones <rjones@redhat.com> - 1.14.2-1
 - Rebase to new stable branch version 1.14.2
   resolves: rhbz#2135764
diff --git a/sources b/sources
index b9be4f3..17e125b 100644
--- a/sources
+++ b/sources
@@ -1,2 +1,2 @@
-SHA512 (libnbd-1.14.2.tar.gz) = ce1aef449a2589734c750ca73d9dc79bf645d08bf7425205f45647b6ec717972568500e50e9546a09bb96a278df77a2752a0a6f50c87237ed3f665dec175ad63
-SHA512 (libnbd-1.14.2.tar.gz.sig) = 264ce543b200728ed17bc5b9b4b99f95aab13c078e01bbe53395dc3e77cfe06f367ec62bf4669824a5ccf573654d9090cc7c649beb95d1e6e3e669e1d2d13732
+SHA512 (libnbd-1.15.12.tar.gz) = fc3ec18d37b9ebcd62f5eeee303a73e5adc0c686d0023bb081020ebd91b7c5708c40d6e3247bb3b3975a0112aa2b8fb9b7d1f9ed7249d2c9fc46d46c75b01775
+SHA512 (libnbd-1.15.12.tar.gz.sig) = 92f967be93a7ac04391152ed1e96cf9f8a384e1dbd1a317c016ad9ef5e6b0f0938a2b92b19960211c019911512cccac3519c5bff9a6062b85dbbcb0f56d4b392