2019年10月31日付けで、Yocto2.6.4(Thud)のリリースがアナウンスされています。
2019/10/17にコミットされたものがQAを経てのリリースとなっています。

本日（日本時間2019年11月1日 17:30)現在、git のbranch thud には、10/17 以降に
更新は行われておりません。

なお、https://www.yoctoproject.org/software-overview/downloads/
にてリンクは作成されていませんが、http://downloads.yoctoproject.org/releases/yocto/yocto-2.6.4/
よりダウンロード可能となっています。

本リリースの詳細は以下のURLにてご確認ください。
https://lists.yoctoproject.org/pipermail/yocto-announce/2019-October/000...

----------------
Known Issues
----------------
Bug 13273 - Systemtap doesn't work on beaglebone
https://bugzilla.yoctoproject.org/show_bug.cgi?id=13273

----------------
Security Fixes
----------------
curl: Security fix for CVE-2019-5482
libsolv: Security fix for CVEs: <CVE-2018-20532, CVE-2018-20533, CVE-2018-20534>
gnutls: Fix CVE-2019-3829 and CVE-2019-3836
glibc: Security fix for cve <CVE-2019-6488, CVE-2019-7309>
wget: Security fixes CVE-2018-20483
sqlite3: Security fix for CVE-2019-8457
perl: Fix CVE-2018-18311 to 18314
unzip: fix CVE-2019-13232
elfutils: CVE fix for elfutils
qemu: Fix 4 CVEs
pango: fix CVE-2019-1010238
patch: fix CVE-2019-13638
libxslt: fix CVE-2019-13117 CVE-2019-13118
libxslt: Cve fix CVE-2019-11068
python3: Fix CVEs
python: Fix 3 CVEs
binutils: Fix 4 CVEs
binutils: Security fix for CVE-2019-12972
binutils: Security fix for CVE-2019-14444
gcc: Security fix for CVE-2019-14250
libcomps: fix CVE-2019-3817
glib-2.0: fix CVE-2019-13012
dbus: fix CVE-2019-12749
curl: fix CVE-2018-16890 CVE-2019-3822 CVE-2019-3823
python3: fix CVE-2019-9740
patch: fix CVE-2019-13636

----------------
Fixes
---------------
build-appliance-image: Update to thud head revision
Revert "OpkgPM: use --add-ignore-recommends to process BAD_RECOMMENDATIONS"
build-appliance-image: Update to thud head revision
poky.conf: Bump version for 2.6.4 thud release
kernel-devsrc: check for localversion files in the kernel source tree
arch-arm64.inc: Lower the priority of aarch64 in MACHINEOVERRIDES
kernel.bbclass: fix installation of modules signing certificates
bitbake: cookerdata: Add mc conffiles hashes to cache hash
uninative: Update to 2.7 release
gnupg: Do not apply -Woverride-init guard for gcc >= 9
libgpg-error: Fix build with gawk 5.x
qemu: fix build issue on new hosts with glibc 2.30
json-c: Don't --enable-rdrand
oeqa/selftest/context: ensure log directory exists
linux-yocto/4.14: update to v4.14.143
patch: backport fixes
dhcp: Replace OE specific patch for compatibility with latest bind with upstream patch
dhcp: drop lost patch
dhcp: fix issue with new bind changes
go: update to 1.11.13, minor updates
bind: upgrade 9.11.5 -> 9.11.5-P4
bind: update to latest LTS 9.11.5
qemu: add a patch fixing the native build on newer kernels
buildhistory: call a dependency parser only on actual dependency lists
bitbake: tests/fetch: Resolve fetch error in bitbake-selftest
YP Docs: Set up the August 2019 date for 2.6.3 release.
bitbake: fetch2: show warning when renaming the archive with bad checksum failed
bitbake: utils: Fix movefile() exception handling with python3