diff --git a/CHANGELOG.md b/CHANGELOG.md
index f2eb37a74..66e3e17cf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,9 @@
 
 ### v1.12.1
 
+**v1.12.1.3** *(2016-07-07)* - [[Userscript](https://raw.githubusercontent.com/ccd0/4chan-x/1.12.1.3/builds/4chan-X-noupdate.user.js)] [[Chrome extension](https://raw.githubusercontent.com/ccd0/4chan-x/1.12.1.3/builds/4chan-X-noupdate.crx)]
+- Fix error message in MathJax popups in Firefox.
+
 **v1.12.1.2** *(2016-07-07)* - [[Userscript](https://raw.githubusercontent.com/ccd0/4chan-x/1.12.1.2/builds/4chan-X-noupdate.user.js)] [[Chrome extension](https://raw.githubusercontent.com/ccd0/4chan-x/1.12.1.2/builds/4chan-X-noupdate.crx)]
 - Merge branch 'bstable'
 - Release 4chan X v1.12.0.9.
diff --git a/builds/4chan-X-beta.crx b/builds/4chan-X-beta.crx
index 9627c1bec..a7933b413 100644
Binary files a/builds/4chan-X-beta.crx and b/builds/4chan-X-beta.crx differ
diff --git a/builds/4chan-X-beta.meta.js b/builds/4chan-X-beta.meta.js
index cdd94e667..c2051a5ba 100644
--- a/builds/4chan-X-beta.meta.js
+++ b/builds/4chan-X-beta.meta.js
@@ -1,6 +1,6 @@
 // ==UserScript==
 // @name         4chan X beta
-// @version      1.12.1.2
+// @version      1.12.1.3
 // @minGMVer     1.14
 // @minFFVer     26
 // @namespace    4chan-X
diff --git a/builds/4chan-X-beta.user.js b/builds/4chan-X-beta.user.js
index 2e1b8b829..9d8abf203 100644
--- a/builds/4chan-X-beta.user.js
+++ b/builds/4chan-X-beta.user.js
@@ -1,6 +1,6 @@
 // ==UserScript==
 // @name         4chan X beta
-// @version      1.12.1.2
+// @version      1.12.1.3
 // @minGMVer     1.14
 // @minFFVer     26
 // @namespace    4chan-X
@@ -136,7 +136,7 @@ docSet = function() {
 };
 
 g = {
-  VERSION:   '1.12.1.2',
+  VERSION:   '1.12.1.3',
   NAMESPACE: '4chan X.',
   boards:    {}
 };
@@ -22356,6 +22356,9 @@ Main = (function() {
           return;
         }
       } catch (_error) {}
+      if (d.documentElement && !d.doctype) {
+        return;
+      }
       $.on(d, '4chanXInitFinished', function() {
         if (Main.expectInitFinished) {
           return delete Main.expectInitFinished;
diff --git a/builds/4chan-X-noupdate.crx b/builds/4chan-X-noupdate.crx
index 9ef9e139a..6fdc62825 100644
Binary files a/builds/4chan-X-noupdate.crx and b/builds/4chan-X-noupdate.crx differ
diff --git a/builds/4chan-X-noupdate.user.js b/builds/4chan-X-noupdate.user.js
index 616502166..020d37a2e 100644
--- a/builds/4chan-X-noupdate.user.js
+++ b/builds/4chan-X-noupdate.user.js
@@ -1,6 +1,6 @@
 // ==UserScript==
 // @name         4chan X
-// @version      1.12.1.2
+// @version      1.12.1.3
 // @minGMVer     1.14
 // @minFFVer     26
 // @namespace    4chan-X
@@ -136,7 +136,7 @@ docSet = function() {
 };
 
 g = {
-  VERSION:   '1.12.1.2',
+  VERSION:   '1.12.1.3',
   NAMESPACE: '4chan X.',
   boards:    {}
 };
@@ -22356,6 +22356,9 @@ Main = (function() {
           return;
         }
       } catch (_error) {}
+      if (d.documentElement && !d.doctype) {
+        return;
+      }
       $.on(d, '4chanXInitFinished', function() {
         if (Main.expectInitFinished) {
           return delete Main.expectInitFinished;
diff --git a/builds/4chan-X.crx b/builds/4chan-X.crx
index 3826e69fb..6aa3c00a6 100644
Binary files a/builds/4chan-X.crx and b/builds/4chan-X.crx differ
diff --git a/builds/4chan-X.meta.js b/builds/4chan-X.meta.js
index 3d0f76397..05d980ae2 100644
--- a/builds/4chan-X.meta.js
+++ b/builds/4chan-X.meta.js
@@ -1,6 +1,6 @@
 // ==UserScript==
 // @name         4chan X
-// @version      1.12.1.2
+// @version      1.12.1.3
 // @minGMVer     1.14
 // @minFFVer     26
 // @namespace    4chan-X
diff --git a/builds/4chan-X.user.js b/builds/4chan-X.user.js
index 7b6bc825c..67aaeca24 100644
--- a/builds/4chan-X.user.js
+++ b/builds/4chan-X.user.js
@@ -1,6 +1,6 @@
 // ==UserScript==
 // @name         4chan X
-// @version      1.12.1.2
+// @version      1.12.1.3
 // @minGMVer     1.14
 // @minFFVer     26
 // @namespace    4chan-X
@@ -136,7 +136,7 @@ docSet = function() {
 };
 
 g = {
-  VERSION:   '1.12.1.2',
+  VERSION:   '1.12.1.3',
   NAMESPACE: '4chan X.',
   boards:    {}
 };
@@ -22356,6 +22356,9 @@ Main = (function() {
           return;
         }
       } catch (_error) {}
+      if (d.documentElement && !d.doctype) {
+        return;
+      }
       $.on(d, '4chanXInitFinished', function() {
         if (Main.expectInitFinished) {
           return delete Main.expectInitFinished;
diff --git a/builds/4chan-X.zip b/builds/4chan-X.zip
index 6187cab0a..7d4d156c4 100644
Binary files a/builds/4chan-X.zip and b/builds/4chan-X.zip differ
diff --git a/builds/updates-beta.xml b/builds/updates-beta.xml
index 6f3832f8d..529f915d6 100644
--- a/builds/updates-beta.xml
+++ b/builds/updates-beta.xml
@@ -1,7 +1,7 @@
 <?xml version='1.0' encoding='UTF-8'?>
 <gupdate xmlns='http://www.google.com/update2/response' protocol='2.0'>
   <app appid='lacclbnghgdicfifcamcmcnilckjamag'>
-    <updatecheck codebase='https://www.4chan-x.net/builds/4chan-X-beta.crx' version='1.12.1.2' />
+    <updatecheck codebase='https://www.4chan-x.net/builds/4chan-X-beta.crx' version='1.12.1.3' />
   </app>
 </gupdate>
 
diff --git a/builds/updates.xml b/builds/updates.xml
index 3d7651d32..a73e0244a 100644
--- a/builds/updates.xml
+++ b/builds/updates.xml
@@ -1,7 +1,7 @@
 <?xml version='1.0' encoding='UTF-8'?>
 <gupdate xmlns='http://www.google.com/update2/response' protocol='2.0'>
   <app appid='lacclbnghgdicfifcamcmcnilckjamag'>
-    <updatecheck codebase='https://www.4chan-x.net/builds/4chan-X.crx' version='1.12.1.2' />
+    <updatecheck codebase='https://www.4chan-x.net/builds/4chan-X.crx' version='1.12.1.3' />
   </app>
 </gupdate>
 
diff --git a/version.json b/version.json
index 3e020275b..48c73fbcd 100644
--- a/version.json
+++ b/version.json
@@ -1,4 +1,4 @@
 {
-  "version": "1.12.1.2",
-  "date": "2016-07-07T15:48:51.980Z"
+  "version": "1.12.1.3",
+  "date": "2016-07-07T23:01:41.318Z"
 }
\ No newline at end of file