diff --git a/.gitignore b/.gitignore
index e1f3642..fa57a27 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,5 @@
 SOURCES/cbindgen-vendor.tar.xz
 SOURCES/nspr-4.32.0-1.el8_1.src.rpm
 SOURCES/nss-3.67.0-7.el8_1.src.rpm
-SOURCES/thunderbird-91.9.0.processed-source.tar.xz
-SOURCES/thunderbird-langpacks-91.9.0-20220503.tar.xz
+SOURCES/thunderbird-91.9.1.processed-source.tar.xz
+SOURCES/thunderbird-langpacks-91.9.1-20220523.tar.xz
diff --git a/.thunderbird.metadata b/.thunderbird.metadata
index 437aa41..97b8738 100644
--- a/.thunderbird.metadata
+++ b/.thunderbird.metadata
@@ -1,5 +1,5 @@
 c822547dbc12e2baebdfdfb38b665e23f0c2513a SOURCES/cbindgen-vendor.tar.xz
 b5fd1332d8e0d37339ae170c7bebcb63a40b22e0 SOURCES/nspr-4.32.0-1.el8_1.src.rpm
 8fff814901e03c2518ede2f8992d898f5ba61ed9 SOURCES/nss-3.67.0-7.el8_1.src.rpm
-e012b11182f73663668bd7f3ebe84acd6e51b44d SOURCES/thunderbird-91.9.0.processed-source.tar.xz
-7cc62140aef4a07dec14fcae4103f57e11859ec1 SOURCES/thunderbird-langpacks-91.9.0-20220503.tar.xz
+4a4c1c234f9e16c184726d8327f4788402e93b82 SOURCES/thunderbird-91.9.1.processed-source.tar.xz
+fb1e4275d84a8ef4f9b3ad82ef759f35e25034b5 SOURCES/thunderbird-langpacks-91.9.1-20220523.tar.xz
diff --git a/SOURCES/python-missing-utimensat.patch b/SOURCES/python-missing-utimensat.patch
new file mode 100644
index 0000000..d19ecab
--- /dev/null
+++ b/SOURCES/python-missing-utimensat.patch
@@ -0,0 +1,12 @@
+diff -up python3/Python-3.6.8/configure.old python3/Python-3.6.8/configure
+--- Python-3.6.8/configure.old	2019-10-01 12:56:35.074551835 +0200
++++ Python-3.6.8/configure	2019-10-01 12:56:44.240517798 +0200
+@@ -11438,7 +11438,7 @@ for ac_func in alarm accept4 setitimer g
+  sigaction sigaltstack siginterrupt sigpending sigrelse \
+  sigtimedwait sigwait sigwaitinfo snprintf strftime strlcpy symlinkat sync \
+  sysconf tcgetpgrp tcsetpgrp tempnam timegm times tmpfile tmpnam tmpnam_r \
+- truncate uname unlinkat unsetenv utimensat utimes waitid waitpid wait3 wait4 \
++ truncate uname unlinkat unsetenv utimes waitid waitpid wait3 wait4 \
+  wcscoll wcsftime wcsxfrm wmemcmp writev _getpty
+ do :
+   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
diff --git a/SPECS/thunderbird.spec b/SPECS/thunderbird.spec
index f2400b8..d7071f2 100644
--- a/SPECS/thunderbird.spec
+++ b/SPECS/thunderbird.spec
@@ -126,10 +126,18 @@ end}
 
 %global official_branding       1
 %global build_langpacks         1
+
+# Workaround the dreaded "upstream source file changed content" rpmdiff failure that only secalert can waive.
+# If set to .b2 or .b3 ... the processed source file needs to be renamed before upload, e.g.
+# thunderbird-91.9.0.b2.processed-source.tar.xz
+# With does_not_exist it's empty and source file name as is.
+#global buildnum %{?does_not_exist}
+%global buildnum %{?does_not_exist}
+
 Summary:        Mozilla Thunderbird mail/newsgroup client
 Name:           thunderbird
-Version:        91.9.0
-Release:        3%{?dist}
+Version:        91.9.1
+Release:        1%{?dist}
 URL:            http://www.mozilla.org/projects/thunderbird/
 License:        MPLv1.1 or GPLv2+ or LGPLv2+
 Group:          Applications/Internet
@@ -153,9 +161,9 @@ ExcludeArch:    s390 ppc
 # The official tarball has to be always processed by the process-official-tarball
 # script.
 # Link to official tarball: https://archive.mozilla.org/pub/thunderbird/releases/%%{version}%%{?pre_version}/source/thunderbird-%%{version}%%{?pre_version}.source.tar.xz
-Source0:        thunderbird-%{version}%{?pre_version}.processed-source.tar.xz
+Source0:        thunderbird-%{version}%{?pre_version}%{?buildnum}.processed-source.tar.xz
 %if %{build_langpacks}
-Source1:        thunderbird-langpacks-%{version}%{?ext_version}-20220503.tar.xz
+Source1:        thunderbird-langpacks-%{version}%{?ext_version}-20220523.tar.xz
 %endif
 Source2:        cbindgen-vendor.tar.xz
 Source3:        get-calendar-langpacks.sh
@@ -176,6 +184,7 @@ Source402:      nspr-4.32.0-1.el8_1.src.rpm
 # Build patches
 # workaround for https://bugzilla.redhat.com/show_bug.cgi?id=1699374
 Patch1001:      build-ppc64le-inline.patch
+Patch1003:      python-missing-utimensat.patch
 Patch1008:        build-rhel7-nasm-dwarf.patch
 Patch1009:        build-debuginfo-fix.patch
 # workaround for https://bugzilla.redhat.com/show_bug.cgi?id=1699374
@@ -1133,6 +1142,9 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
 #===============================================================================
 
 %changelog
+* Mon May 23 2022 Jan Horak <jhorak@redhat.com> - 91.9.1-1
+- Update to 91.9.1 build1
+
 * Tue May 03 2022 Eike Rathke <erack@redhat.com> - 91.9.0-3
 - Update to 91.9.0 build3
 
@@ -1157,9 +1169,6 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
 * Fri Jan 07 2022 Eike Rathke <erack@redhat.com> - 91.5.0-1
 - Update to 91.5.0 build1
 
-* Tue Dec 07 2021 Eike Rathke <erack@redhat.com> - 91.4.0-3
-- Bump NVR for ppc64 build
-
 * Mon Dec 06 2021 Eike Rathke <erack@redhat.com> - 91.4.0-2
 - Update to 91.4.0 build2