diff --git a/network/mail/thunderbird/files/pisilinux/mozconfig b/network/mail/thunderbird/files/pisilinux/mozconfig
index 92541a1bf1..986548a4aa 100644
--- a/network/mail/thunderbird/files/pisilinux/mozconfig
+++ b/network/mail/thunderbird/files/pisilinux/mozconfig
@@ -1,4 +1,4 @@
-mk_add_options MOZ_MAKE_FLAGS="-j5"
+mk_add_options MOZ_MAKE_FLAGS="##JOBCOUNT##"
 
 ac_add_options --prefix=/usr
 ac_add_options --enable-release
diff --git a/network/mail/thunderbird/pspec.xml b/network/mail/thunderbird/pspec.xml
index be1f1fe790..17f82b4932 100644
--- a/network/mail/thunderbird/pspec.xml
+++ b/network/mail/thunderbird/pspec.xml
@@ -15,7 +15,7 @@
         <IsA>app:gui</IsA>
         <Summary>The Stand-Alone Mozilla Mail Component</Summary>
         <Description>Thunderbird is a redesign of the Mozilla Mail Component. It is written using the XUL user interface language and designed to be cross-platform.</Description>
-        <Archive sha1sum="aaf8fe931346caefdf50256053d7c2df742ef83f" type="tarxz">http://ftp.mozilla.org/pub/thunderbird/releases/115.4.1/source/thunderbird-115.4.1.source.tar.xz</Archive>
+        <Archive sha1sum="9eb1331ce64707d621c54cd08a95b896d0df6130" type="tarxz">http://ftp.mozilla.org/pub/thunderbird/releases/115.5.1/source/thunderbird-115.5.1.source.tar.xz</Archive>
         <AdditionalFiles>
             <AdditionalFile target=".mozconfig">pisilinux/mozconfig</AdditionalFile>
         </AdditionalFiles>
@@ -471,6 +471,13 @@
     </Package>
 
     <History>
+        <Update release="13">
+            <Date>2023-11-29</Date>
+            <Version>115.5.1</Version>
+            <Comment>Version bump.</Comment>
+            <Name>Mustafa Cinasal</Name>
+            <Email>muscnsl@gmail.com</Email>
+        </Update>
         <Update release="12">
             <Date>2023-10-28</Date>
             <Version>115.4.1</Version>