diff --git a/introduction/welcome/changelog.xml b/introduction/welcome/changelog.xml
index e33f8bb355..627034d0db 100644
--- a/introduction/welcome/changelog.xml
+++ b/introduction/welcome/changelog.xml
@@ -41,6 +41,10 @@
    <listitem>
      <para>August 23rd, 2023</para>
      <itemizedlist>
+       <listitem>
+         <para>[renodr] - Update to Thunderbird-115.1.1 (Security Update).
+         Fixes <ulink url="&blfs-ticket-root;18323">#18323</ulink>.</para>
+       </listitem>
        <listitem>
          <para>[renodr] - Update to gnome-system-monitor-45.0. Fixes
          <ulink url="&blfs-ticket-root;18430">#18430</ulink>.</para>
diff --git a/packages.ent b/packages.ent
index 7fc3ac14e2..c1d510fd30 100644
--- a/packages.ent
+++ b/packages.ent
@@ -1004,7 +1004,7 @@ to avoid building libxml2 twice, which is slow with all deps -->
 <!ENTITY pidgin-version               "2.14.12">
 <!ENTITY rox-filer-version            "2.11">
 <!ENTITY rxvt-unicode-version         "9.31">
-<!ENTITY thunderbird-version          "115.0">
+<!ENTITY thunderbird-version          "115.1.1">
 <!ENTITY tigervnc-version             "1.13.1">
 <!ENTITY transmission-version         "4.0.3">
 <!ENTITY xarchiver-version            "0.5.4.21">
diff --git a/xsoft/other/thunderbird.xml b/xsoft/other/thunderbird.xml
index 6f3b8bb03b..d4dbf8b484 100644
--- a/xsoft/other/thunderbird.xml
+++ b/xsoft/other/thunderbird.xml
@@ -6,10 +6,10 @@
 
   <!ENTITY thunderbird-download-http "&mozilla-http;/thunderbird/releases/&thunderbird-version;/source/thunderbird-&thunderbird-version;.source.tar.xz">
   <!ENTITY thunderbird-download-ftp  " ">
-  <!ENTITY thunderbird-md5sum        "4113a557a9730e4af8891ee7d7e27883">
-  <!ENTITY thunderbird-size          "507 MB">
-  <!ENTITY thunderbird-buildsize     "7.3 GB (205 MB installed)">
-  <!ENTITY thunderbird-time          "20 SBU (on a 4-core machine)">
+  <!ENTITY thunderbird-md5sum        "e4694b8b4a61211a4a7a34e8c6878ff3">
+  <!ENTITY thunderbird-size          "508 MB">
+  <!ENTITY thunderbird-buildsize     "6.7 GB (236 MB installed)">
+  <!ENTITY thunderbird-time          "22 SBU (on a 4-core machine)">
   <!-- Removed the -j1 time because python and rust do not obey it, although
        the C/C++ code appears to obey it.
 
@@ -36,7 +36,7 @@
       Gecko rendering engine to enable it to display and compose HTML emails.
     </para>
 
-    &lfs113_checked;
+    &lfs120_checked;
 
     <bridgehead renderas="sect3">Package Information</bridgehead>
     <itemizedlist spacing="compact">
@@ -95,7 +95,11 @@
 
     <bridgehead renderas="sect4">Recommended</bridgehead>
     <para role="recommended">
-      <xref linkend="icu"/>,
+      <!-- When using system ICU, a problem occurs where the calendar and mail
+           functions do not render correctly and it causes other strange
+           behavior to occur. See Ticket #18323 for more details, as well as
+           https://lore.kernel.org/distributions/075a20b1-869b-78f3-9ace-e106a4d43ac4@linuxlounge.net/T/#u -->
+      <!--<xref linkend="icu"/>,-->
       <xref linkend="libevent"/>,
       <xref linkend="libvpx"/>,
       <xref linkend="nasm"/>,
@@ -164,7 +168,6 @@ ac_add_options --with-system-libevent
 ac_add_options --with-system-libvpx
 ac_add_options --with-system-nspr
 ac_add_options --with-system-nss
-ac_add_options --with-system-icu
 
 # The elf-hack causes failed installs on some machines.
 # It is supposed to improve startup time and it shrinks libxul.so