diff --git a/nbdkit.spec b/nbdkit.spec
index 7dd3a1e..61c9c09 100644
--- a/nbdkit.spec
+++ b/nbdkit.spec
@@ -51,11 +51,11 @@
 %global verify_tarball_signature 1
 
 # The source directory.
-%global source_directory 1.38-stable
+%global source_directory 1.40-stable
 
 Name:           nbdkit
-Version:        1.38.0
-Release:        6%{?dist}
+Version:        1.40.0
+Release:        1%{?dist}
 Summary:        NBD server
 
 License:        BSD-3-Clause
@@ -95,28 +95,31 @@ BuildRequires:  autoconf, automake, libtool
 BuildRequires:  make
 BuildRequires:  gcc, gcc-c++
 BuildRequires:  %{_bindir}/pod2man
-BuildRequires:  gnutls-devel
-BuildRequires:  libselinux-devel
+BuildRequires:  pkgconfig(gnutls)
+BuildRequires:  pkgconfig(libselinux)
 %if !0%{?rhel} && 0%{?have_libguestfs}
-BuildRequires:  libguestfs-devel
+BuildRequires:  pkgconfig(libguestfs)
 %endif
-BuildRequires:  libvirt-devel
-BuildRequires:  xz-devel
-BuildRequires:  zlib-devel
+BuildRequires:  pkgconfig(libvirt)
+BuildRequires:  pkgconfig(liblzma)
+BuildRequires:  pkgconfig(zlib)
 %if !0%{?rhel}
-BuildRequires:  zlib-ng-devel
+BuildRequires:  pkgconfig(zlib-ng)
 %endif
-BuildRequires:  libzstd-devel
-BuildRequires:  libcurl-devel
-BuildRequires:  libnbd-devel >= 1.3.11
-BuildRequires:  libssh-devel
-BuildRequires:  e2fsprogs, e2fsprogs-devel
+BuildRequires:  pkgconfig(bzip2)
+BuildRequires:  pkgconfig(libzstd)
+BuildRequires:  pkgconfig(libcurl)
+BuildRequires:  pkgconfig(libnbd)
+BuildRequires:  pkgconfig(libssh)
+BuildRequires:  e2fsprogs
+BuildRequires:  pkgconfig(ext2fs)
+BuildRequires:  pkgconfig(com_err)
 %if !0%{?rhel}
 BuildRequires:  xorriso
-BuildRequires:  rb_libtorrent-devel
+BuildRequires:  pkgconfig(libtorrent-rasterbar)
 %endif
 %if 0%{?have_blkio}
-BuildRequires:  libblkio-devel
+BuildRequires:  pkgconfig(blkio)
 %endif
 BuildRequires:  bash-completion
 BuildRequires:  perl-devel
@@ -134,9 +137,13 @@ BuildRequires:  python3-boto3
 BuildRequires:  ocaml >= 4.03
 BuildRequires:  ocaml-ocamldoc
 %endif
-BuildRequires:  ruby-devel
-BuildRequires:  tcl-devel
-BuildRequires:  lua-devel
+BuildRequires:  pkgconfig(tcl)
+BuildRequires:  pkgconfig(lua)
+%endif
+# Only needed until the following bug gets fixed in boost:
+# https://bugzilla.redhat.com/show_bug.cgi?id=2297642
+%if 0%{?fedora} >= 41
+BuildRequires:  openssl-devel-engine
 %endif
 %if 0%{verify_tarball_signature}
 BuildRequires:  gnupg2
@@ -224,6 +231,8 @@ The key features are:
 
 * Filters can be stacked in front of plugins to transform the output.
 
+* Server can run standalone or can be invoked from other programs.
+
 '%{name}' is a meta-package which pulls in the core server and a
 useful subset of plugins and filters with minimal dependencies.
 
@@ -250,8 +259,8 @@ Requires:       %{name}-server%{?_isa} = %{version}-%{release}
 
 %description basic-plugins
 This package contains plugins for %{name} which only depend on simple
-C libraries: glibc, gnutls, libzstd.  Other plugins for nbdkit with
-more complex dependencies are packaged separately.
+C libraries: glibc, gnutls, zlib and zstd.  Other plugins for nbdkit
+with more complex dependencies are packaged separately.
 
 nbdkit-data-plugin          Serve small amounts of data from the command line.
 
@@ -464,16 +473,6 @@ Requires:       %{name}-server%{?_isa} = %{version}-%{release}
 This package lets you write Python 3 plugins for %{name}.
 
 
-%if !0%{?rhel}
-%package ruby-plugin
-Summary:        Ruby plugin for %{name}
-Requires:       %{name}-server%{?_isa} = %{version}-%{release}
-
-%description ruby-plugin
-This package lets you write Ruby plugins for %{name}.
-%endif
-
-
 %if !0%{?rhel}
 # In theory this is noarch, but because plugins are placed in _libdir
 # which varies across architectures, RPM does not allow this.
@@ -549,11 +548,13 @@ VMware VDDK for accessing VMware disks and servers.
 %package basic-filters
 Summary:        Basic filters for %{name}
 Requires:       %{name}-server%{?_isa} = %{version}-%{release}
+# Remove this in Fedora 43:
+Obsoletes:      nbdkit-gzip-filter < %{version}-%{release}
 
 %description basic-filters
 This package contains filters for %{name} which only depend on simple
-C libraries: glibc, gnutls.  Other filters for nbdkit with more
-complex dependencies are packaged separately.
+C libraries: glibc, gnutls, zlib and zstd.  Other filters for nbdkit
+with more complex dependencies are packaged separately.
 
 nbdkit-blocksize-filter    Adjust block size of requests sent to plugins.
 
@@ -585,6 +586,8 @@ nbdkit-extentlist-filter   Place extent list over a plugin.
 
 nbdkit-fua-filter          Modify flush behaviour in plugins.
 
+nbdkit-gzip-filter         Decompress a .gz file
+
 nbdkit-ip-filter           Filter clients by IP address.
 
 nbdkit-limit-filter        Limit nr clients that can connect concurrently.
@@ -627,8 +630,12 @@ nbdkit-retry-filter        Reopen connection on error.
 
 nbdkit-retry-request-filter Retry single requests on error.
 
+nbdkit-rotational-filter   Set if a plugin is rotational or not.
+
 nbdkit-scan-filter         Prefetch data ahead of sequential reads.
 
+nbdkit-spinning-filter     Add seek delays to simulate a spinning hard disk.
+
 nbdkit-swab-filter         Filter for swapping byte order.
 
 nbdkit-tls-fallback-filter TLS protection filter.
@@ -636,6 +643,14 @@ nbdkit-tls-fallback-filter TLS protection filter.
 nbdkit-truncate-filter     Truncate, expand, round up or round down size.
 
 
+%package bzip2-filter
+Summary:        BZip2 filter for %{name}
+Requires:       %{name}-server%{?_isa} = %{version}-%{release}
+
+%description bzip2-filter
+This package is a bzip2 filter for %{name}.
+
+
 %if !0%{?rhel}
 %package ext2-filter
 Summary:        ext2, ext3 and ext4 filesystem support for %{name}
@@ -647,14 +662,6 @@ This package contains ext2, ext3 and ext4 filesystem support for
 %endif
 
 
-%package gzip-filter
-Summary:        GZip filter for %{name}
-Requires:       %{name}-server%{?_isa} = %{version}-%{release}
-
-%description gzip-filter
-This package is a gzip filter for %{name}.
-
-
 %package stats-filter
 Summary:        Statistics filter for %{name}
 Requires:       %{name}-server%{?_isa} = %{version}-%{release}
@@ -667,7 +674,6 @@ Display statistics about operations.
 Summary:        Tar archive filter for %{name}
 Requires:       %{name}-server%{?_isa} = %{version}-%{release}
 Requires:       tar
-Obsoletes:      %{name}-tar-plugin < 1.23.9-3
 
 %description tar-filter
 This package is a tar archive filter for %{name}.
@@ -811,7 +817,6 @@ export PYTHON=%{__python3}
 %if !0%{?rhel}
     --enable-lua \
     --enable-perl \
-    --enable-ruby \
     --enable-tcl \
     --enable-torrent \
     --with-ext2 \
@@ -820,7 +825,6 @@ export PYTHON=%{__python3}
 %else
     --disable-lua \
     --disable-perl \
-    --disable-ruby \
     --disable-tcl \
     --disable-torrent \
     --without-ext2 \
@@ -885,7 +889,6 @@ popd
     --disable-ocaml \
     --disable-perl \
     --disable-python \
-    --disable-ruby \
     --disable-rust \
     --disable-tcl \
     --disable-torrent \
@@ -1236,15 +1239,6 @@ fi
 %{_mandir}/man3/nbdkit-python-plugin.3*
 
 
-%if !0%{?rhel}
-%files ruby-plugin
-%doc README.md
-%license LICENSE
-%{_libdir}/%{name}/plugins/nbdkit-ruby-plugin.so
-%{_mandir}/man3/nbdkit-ruby-plugin.3*
-%endif
-
-
 %if !0%{?rhel}
 %files S3-plugin
 %doc README.md
@@ -1313,6 +1307,7 @@ fi
 %{_libdir}/%{name}/filters/nbdkit-exportname-filter.so
 %{_libdir}/%{name}/filters/nbdkit-extentlist-filter.so
 %{_libdir}/%{name}/filters/nbdkit-fua-filter.so
+%{_libdir}/%{name}/filters/nbdkit-gzip-filter.so
 %{_libdir}/%{name}/filters/nbdkit-ip-filter.so
 %{_libdir}/%{name}/filters/nbdkit-limit-filter.so
 %{_libdir}/%{name}/filters/nbdkit-log-filter.so
@@ -1335,7 +1330,9 @@ fi
 %{_libdir}/%{name}/filters/nbdkit-readonly-filter.so
 %{_libdir}/%{name}/filters/nbdkit-retry-filter.so
 %{_libdir}/%{name}/filters/nbdkit-retry-request-filter.so
+%{_libdir}/%{name}/filters/nbdkit-rotational-filter.so
 %{_libdir}/%{name}/filters/nbdkit-scan-filter.so
+%{_libdir}/%{name}/filters/nbdkit-spinning-filter.so
 %{_libdir}/%{name}/filters/nbdkit-swab-filter.so
 %{_libdir}/%{name}/filters/nbdkit-tls-fallback-filter.so
 %{_libdir}/%{name}/filters/nbdkit-truncate-filter.so
@@ -1354,6 +1351,7 @@ fi
 %{_mandir}/man1/nbdkit-exportname-filter.1*
 %{_mandir}/man1/nbdkit-extentlist-filter.1*
 %{_mandir}/man1/nbdkit-fua-filter.1*
+%{_mandir}/man1/nbdkit-gzip-filter.1*
 %{_mandir}/man1/nbdkit-ip-filter.1*
 %{_mandir}/man1/nbdkit-limit-filter.1*
 %{_mandir}/man1/nbdkit-log-filter.1*
@@ -1376,12 +1374,21 @@ fi
 %{_mandir}/man1/nbdkit-readonly-filter.1*
 %{_mandir}/man1/nbdkit-retry-filter.1*
 %{_mandir}/man1/nbdkit-retry-request-filter.1*
+%{_mandir}/man1/nbdkit-rotational-filter.1*
 %{_mandir}/man1/nbdkit-scan-filter.1*
+%{_mandir}/man1/nbdkit-spinning-filter.1*
 %{_mandir}/man1/nbdkit-swab-filter.1*
 %{_mandir}/man1/nbdkit-tls-fallback-filter.1*
 %{_mandir}/man1/nbdkit-truncate-filter.1*
 
 
+%files bzip2-filter
+%doc README.md
+%license LICENSE
+%{_libdir}/%{name}/filters/nbdkit-bzip2-filter.so
+%{_mandir}/man1/nbdkit-bzip2-filter.1*
+
+
 %if !0%{?rhel}
 %files ext2-filter
 %doc README.md
@@ -1391,13 +1398,6 @@ fi
 %endif
 
 
-%files gzip-filter
-%doc README.md
-%license LICENSE
-%{_libdir}/%{name}/filters/nbdkit-gzip-filter.so
-%{_mandir}/man1/nbdkit-gzip-filter.1*
-
-
 %files stats-filter
 %doc README.md
 %license LICENSE
@@ -1435,10 +1435,7 @@ fi
 %doc plugins/perl/example.pl
 %endif
 %doc plugins/python/examples/*.py
-%if !0%{?rhel}
-%doc plugins/ruby/example.rb
-%endif
-%doc plugins/sh/example.sh
+%doc plugins/sh/examples/*.sh
 %if !0%{?rhel}
 %doc plugins/tcl/example.tcl
 %endif
@@ -1449,6 +1446,7 @@ fi
 %{_includedir}/nbd-protocol.h
 %{_mandir}/man3/nbdkit-filter.3*
 %{_mandir}/man3/nbdkit-plugin.3*
+%{_mandir}/man3/nbdkit_*.3*
 %{_mandir}/man1/nbdkit-release-notes-1.*.1*
 %{_libdir}/pkgconfig/nbdkit.pc
 
@@ -1494,6 +1492,10 @@ fi
 
 
 %changelog
+* Mon Jul 22 2024 Richard W.M. Jones <rjones@redhat.com> - 1.40.0-1
+- Rebase to nbdkit 1.40.0
+  related: RHEL-49594
+
 * Fri Jul 12 2024 Richard W.M. Jones <rjones@redhat.com> - 1.38.0-6
 - Re-add libxcrypt dependency
   resolves: RHEL-47272
diff --git a/sources b/sources
index 3b095a3..623be89 100644
--- a/sources
+++ b/sources
@@ -1,2 +1,2 @@
-SHA512 (nbdkit-1.38.0.tar.gz) = 7817ab29f2c4821237ac9114e820186b6fcbe5658fb702ecd41941fc70ffd060294c3d71fbcb37176f4609d3e25996ea71e20ea58d0aee2c8bf6b4b30254d074
-SHA512 (nbdkit-1.38.0.tar.gz.sig) = e81960962737f57c586bbf4dea9b2f7f208bb7258919ddd808006d4d14582ebd8e6b7d0e9f64ed48176c74c8c6ec00f042060be6a91ac0d8db20a1d936a53b42
+SHA512 (nbdkit-1.40.0.tar.gz) = 2ebf416359e61d4a7945ada095363fabfd300a3a9721a07ea39b0682c9d9e4dc0b8a9b1145e7992eca8605727d9c7a20c396295e3412e5e1bd246b903616a68d
+SHA512 (nbdkit-1.40.0.tar.gz.sig) = a3833dc96b241f77ea90bd2a13ec20aaa1e0d72c777fdf7d5dc73271b2df8e8649254b5cface74eddd5952feb9ef6c2191777153edb17674de68a7dabfad54eb