diff --git a/general/genlib/js78.xml b/general/genlib/js78.xml
index ca611478d5..47c9a433eb 100644
--- a/general/genlib/js78.xml
+++ b/general/genlib/js78.xml
@@ -13,10 +13,10 @@
   <!ENTITY ff78-version       "&firefox-version;">
   <!ENTITY js78-download-http "&mozilla-http;/firefox/releases/&ff78-version;esr/source/firefox-&ff78-version;esr.source.tar.xz">
   <!ENTITY js78-download-ftp  " ">
-  <!ENTITY js78-md5sum        "10529ea05d2a1b46eb239330a3ae5471">
-  <!ENTITY js78-size          "318 MB">
-  <!ENTITY js78-buildsize     "2.0 GB (36 MB installed after removing 34MB static lib)">
-  <!ENTITY js78-time          "2.0 SBU (on a 4-core machine)">
+  <!ENTITY js78-md5sum        "b81fc212639eab6a20c0a262e2eee302">
+  <!ENTITY js78-size          "320 MB">
+  <!ENTITY js78-buildsize     "3.0 GB (36 MB installed after removing 34MB static lib)">
+  <!ENTITY js78-time          "2.5 SBU (on a 4-core machine)">
 ]>
 
 <sect1 id="js78" xreflabel="js78-&ff78-version;">
diff --git a/introduction/welcome/changelog.xml b/introduction/welcome/changelog.xml
index 94f5789bcd..b4582a5fab 100644
--- a/introduction/welcome/changelog.xml
+++ b/introduction/welcome/changelog.xml
@@ -42,6 +42,16 @@
     </listitem>
     -->
 
+   <listitem>
+      <para>April 19th, 2021</para>
+      <itemizedlist>
+       <listitem>
+          <para>[ken] - Update to firefox-78.10.0esr (security fixes) and
+          JS-78.10.0.</para>
+        </listitem>
+      </itemizedlist>
+    </listitem>
+
    <listitem>
       <para>April 17th, 2021</para>
       <itemizedlist>
diff --git a/packages.ent b/packages.ent
index ebc2edec73..cf89cbf411 100644
--- a/packages.ent
+++ b/packages.ent
@@ -924,7 +924,7 @@ to avoid building libxml2 twice, which is slow with all deps -->
 <!ENTITY falkon-major-version         "3.1">
 <!ENTITY falkon-minor-version         "0">
 <!ENTITY falkon-version               "&falkon-major-version;.&falkon-minor-version;">
-<!ENTITY firefox-version              "78.9.0">
+<!ENTITY firefox-version              "78.10.0">
 <!ENTITY flashplayer-version          "27.0.0.187">
 <!ENTITY qupzilla-version             "2.2.6">
 <!ENTITY seamonkey-version            "2.53.7">
diff --git a/xsoft/graphweb/firefox.xml b/xsoft/graphweb/firefox.xml
index af2913993f..b609455b7b 100644
--- a/xsoft/graphweb/firefox.xml
+++ b/xsoft/graphweb/firefox.xml
@@ -6,15 +6,15 @@
 
   <!ENTITY firefox-download-http "&mozilla-http;/firefox/releases/&firefox-version;esr/source/firefox-&firefox-version;esr.source.tar.xz">
   <!ENTITY firefox-download-ftp  " ">
-  <!ENTITY firefox-md5sum        "10529ea05d2a1b46eb239330a3ae5471">
-  <!ENTITY firefox-size          "318 MB">
+  <!ENTITY firefox-md5sum        "b81fc212639eab6a20c0a262e2eee302">
+  <!ENTITY firefox-size          "320 MB">
   <!-- NB with stylo, much of the build uses rust, and therefore cargo files.
     But the extra cached cargo files, if any, seem to be minimal -->
-  <!ENTITY firefox-buildsize     "5.1 GB (187 MB installed) without tests">
+  <!ENTITY firefox-buildsize     "5.2 GB (187 MB installed) without tests">
   <!-- editors: with ff63 and rust-1.29, ./mach build -j4 is probably the
    most practical way to get a timing on a machine with more cores, if taking
    cores offline is not practical. If in doubt, round up -->
-  <!ENTITY firefox-time          "22 SBU (on a 4-core machine) without tests">
+  <!ENTITY firefox-time          "28 SBU (on a 4-core machine) without tests">
 ]>
 
 <sect1 id="firefox" xreflabel="Firefox-&firefox-version;">