diff --git a/.gitignore b/.gitignore
index 4f671dc..65517d1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,6 @@ SOURCES/cbindgen-vendor.tar.xz
 SOURCES/nspr-4.35.0-1.el8_1.src.rpm
 SOURCES/nss-3.90.0-2.el8_1.src.rpm
 SOURCES/nss-3.90.0-3.el9_0.src.rpm
-SOURCES/thunderbird-115.4.1.processed-source.tar.xz
-SOURCES/thunderbird-langpacks-115.4.1-20231025.tar.xz
+SOURCES/thunderbird-115.5.0.processed-source.tar.xz
+SOURCES/thunderbird-langpacks-115.5.0-20231121.tar.xz
 SOURCES/thunderbird-symbolic.svg
diff --git a/.thunderbird.metadata b/.thunderbird.metadata
index be6cb3f..b09195f 100644
--- a/.thunderbird.metadata
+++ b/.thunderbird.metadata
@@ -2,6 +2,6 @@ b963b16f6879c5dbe6e33a3a3da058b494453922 SOURCES/cbindgen-vendor.tar.xz
 d744f92e874688cc4b5376477dfdd639a97a6cd4 SOURCES/nspr-4.35.0-1.el8_1.src.rpm
 39d1004f8948186cdaa33bbb90423f6f994bdf6c SOURCES/nss-3.90.0-2.el8_1.src.rpm
 df0dd588680f6ade6728a1fd3ff2d71e7a46255d SOURCES/nss-3.90.0-3.el9_0.src.rpm
-02fe5168662a55fdad1abfe4537442ca9cac6f67 SOURCES/thunderbird-115.4.1.processed-source.tar.xz
-7fb41ab4b51c0b38cc104092300d61fdea062de0 SOURCES/thunderbird-langpacks-115.4.1-20231025.tar.xz
+5a7ac4a9bd48e160ad1fcac18f4bb2660f5672e1 SOURCES/thunderbird-115.5.0.processed-source.tar.xz
+659e4bde9e34477277c3a7e6d09457cbe9340b44 SOURCES/thunderbird-langpacks-115.5.0-20231121.tar.xz
 42e80b86948cdba0f69af5b15a69bc6a1274d938 SOURCES/thunderbird-symbolic.svg
diff --git a/README.debrand b/README.debrand
deleted file mode 100644
index 01c46d2..0000000
--- a/README.debrand
+++ /dev/null
@@ -1,2 +0,0 @@
-Warning: This package was configured for automatic debranding, but the changes
-failed to apply.
diff --git a/SPECS/thunderbird.spec b/SPECS/thunderbird.spec
index 1d51290..d71c4df 100644
--- a/SPECS/thunderbird.spec
+++ b/SPECS/thunderbird.spec
@@ -134,7 +134,7 @@ end}
 
 Summary:        Mozilla Thunderbird mail/newsgroup client
 Name:           thunderbird
-Version:        115.4.1
+Version:        115.5.0
 Release:        1%{?dist}
 URL:            http://www.mozilla.org/projects/thunderbird/
 License:        MPLv1.1 or GPLv2+ or LGPLv2+
@@ -143,14 +143,19 @@ License:        MPLv1.1 or GPLv2+ or LGPLv2+
 ExcludeArch:    %{ix86}
 %endif
 %if 0%{?rhel} == 8
+  # Started to ship on aarch64 in RHEL 8.2, on s390x in RHEL 8.3
   %if %{rhel_minor_version} == 1
-ExcludeArch:    %{ix86} aarch64 s390x
+ExcludeArch:    %{ix86} s390x aarch64
   %else
+    %if %{rhel_minor_version} == 2
+ExcludeArch:    %{ix86} s390x
+    %else
 ExcludeArch:    %{ix86}
+    %endif
   %endif
 %endif
 %if 0%{?rhel} == 7
-ExcludeArch:    aarch64 s390 ppc
+ExcludeArch:    aarch64 s390 ppc ppc64
 %endif
 
 # We can't use the official tarball as it contains some test files that use
@@ -160,7 +165,7 @@ ExcludeArch:    aarch64 s390 ppc
 #Source0:        https://archive.mozilla.org/pub/thunderbird/releases/%%{version}%%{?pre_version}/source/thunderbird-%%{version}%%{?pre_version}.processed-source.tar.xz
 Source0:        thunderbird-%{version}%{?pre_version}%{?buildnum}.processed-source.tar.xz
 %if %{with langpacks}
-Source1:        thunderbird-langpacks-%{version}-20231025.tar.xz
+Source1:        thunderbird-langpacks-%{version}-20231121.tar.xz
 %endif
 Source2:        cbindgen-vendor.tar.xz
 Source3:        process-official-tarball
@@ -1014,6 +1019,13 @@ echo "ac_add_options --with-mozilla-api-keyfile=`pwd`/mozilla-api-key" >> .mozco
 echo "ac_add_options --with-google-location-service-api-keyfile=`pwd`/google-loc-api-key" >> .mozconfig
 echo "ac_add_options --with-google-safebrowsing-api-keyfile=`pwd`/google-api-key" >> .mozconfig
 
+# May result in empty --with-libclang-path= in earlier versions.
+# So far this is needed only for c8s.
+%if 0%{?rhel} == 8 && %{rhel_minor_version} >= 10
+# Clang 17 upstream's detection fails, tell it where to look.
+echo "ac_add_options --with-libclang-path=`llvm-config --libdir`" >> .mozconfig
+%endif
+
 echo 'export NODEJS="%{_buildrootdir}/bin/node-stdout-nonblocking-wrapper"' >> .mozconfig
 
 # Remove executable bit to make brp-mangle-shebangs happy.
@@ -1502,6 +1514,9 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
 #===============================================================================
 
 %changelog
+* Tue Nov 21 2023 Eike Rathke <erack@redhat.com> - 115.5.0-1
+- Update to 115.5.0 build1
+
 * Wed Oct 25 2023 Eike Rathke <erack@redhat.com> - 115.4.1-1
 - Update to 115.4.1 build1