diff --git a/README.md b/README.md
index 3479f2b75..e2a28ae02 100644
--- a/README.md
+++ b/README.md
@@ -33,9 +33,9 @@ PDF.js is built into version 19+ of Firefox, however, one extension is still ava
 
 + [Development Version](http://mozilla.github.io/pdf.js/extensions/firefox/pdf.js.xpi) - This extension is mainly intended for developers/testers, and it is updated every time new code is merged into the PDF.js codebase. It should be quite stable but might break from time to time.
 
-  + Please note that the extension is *not* guaranteed to be compatible with Firefox versions that are *older* than the current ESR version, see the [Release Calendar](https://wiki.mozilla.org/RapidRelease/Calendar#Past_branch_dates).
+  + Please note that the extension is *not* guaranteed to be compatible with Firefox versions that are *older* than the current Nightly version, see the [Release Calendar](https://wiki.mozilla.org/RapidRelease/Calendar#Past_branch_dates).
 
-  + The extension should also work in Seamonkey, provided that it is based on a Firefox version as above (see [Which version of Firefox does SeaMonkey 2.x correspond with?](https://wiki.mozilla.org/SeaMonkey/FAQ#General)), but we do *not* guarantee compatibility.
+  + The extension *may* also work in Seamonkey, provided that it is based on a Firefox version as above (see [Which version of Firefox does SeaMonkey 2.x correspond with?](https://wiki.mozilla.org/SeaMonkey/FAQ#General)), but we do *not* guarantee compatibility.
 
 #### Chrome
 
diff --git a/extensions/firefox/install.rdf b/extensions/firefox/install.rdf
index ad00cab3a..5d010b003 100644
--- a/extensions/firefox/install.rdf
+++ b/extensions/firefox/install.rdf
@@ -13,8 +13,8 @@
     <em:targetApplication>
       <Description>
        <em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id>
-       <em:minVersion>45.0</em:minVersion>
-       <em:maxVersion>54.0a1</em:maxVersion>
+       <em:minVersion>59.*</em:minVersion>
+       <em:maxVersion>61.0a1</em:maxVersion>
      </Description>
     </em:targetApplication>
 
@@ -31,8 +31,8 @@
     <em:targetApplication>
       <Description>
        <em:id>{aa3c5121-dab2-40e2-81ca-7ea25febc110}</em:id>
-       <em:minVersion>45.0</em:minVersion>
-       <em:maxVersion>54.0a1</em:maxVersion>
+       <em:minVersion>59.*</em:minVersion>
+       <em:maxVersion>61.0a1</em:maxVersion>
      </Description>
     </em:targetApplication>
 
diff --git a/extensions/firefox/update.rdf b/extensions/firefox/update.rdf
index 260a1f33f..b74b618c7 100644
--- a/extensions/firefox/update.rdf
+++ b/extensions/firefox/update.rdf
@@ -14,8 +14,8 @@
             <em:targetApplication>
               <RDF:Description>
                 <em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id>
-                <em:minVersion>45.0</em:minVersion>
-                <em:maxVersion>54.0a1</em:maxVersion>
+                <em:minVersion>59.*</em:minVersion>
+                <em:maxVersion>61.0a1</em:maxVersion>
                 <!-- Use the raw link for updates so we we can use SSL. -->
                 <em:updateLink>https://raw.githubusercontent.com/mozilla/pdf.js/gh-pages/extensions/firefox/pdf.js.xpi</em:updateLink>
               </RDF:Description>
@@ -25,8 +25,8 @@
             <em:targetApplication>
               <RDF:Description>
                 <em:id>{aa3c5121-dab2-40e2-81ca-7ea25febc110}</em:id>
-                <em:minVersion>45.0</em:minVersion>
-                <em:maxVersion>54.0a1</em:maxVersion>
+                <em:minVersion>59.*</em:minVersion>
+                <em:maxVersion>61.0a1</em:maxVersion>
                 <!-- Use the raw link for updates so we we can use SSL. -->
                 <em:updateLink>https://raw.githubusercontent.com/mozilla/pdf.js/gh-pages/extensions/firefox/pdf.js.xpi</em:updateLink>
               </RDF:Description>