diff --git a/src/common/options-store.js b/src/common/options-store.js
index 447d8af5..1df85b05 100644
--- a/src/common/options-store.js
+++ b/src/common/options-store.js
@@ -303,85 +303,65 @@ var MozillaOptionsStore = {
   // directly. Unfortunately, this means duplicating some code from the background
   // service.
   _sendRequest: function(data, callback) { // analogue of chrome.runtime.sendMessage
-    var extPrefsBranch, supportString, prefKeys, prefsObj, request, sender, i;
-
-    try {
-      extPrefsBranch = window.Components.classes['@mozilla.org/preferences-service;1']
-                             .getService(Components.interfaces.nsIPrefService)
-                             .getBranch('extensions.markdown-here.');
-      supportString = Components.classes["@mozilla.org/supports-string;1"]
-                                .createInstance(Components.interfaces.nsISupportsString);
-
-      if (data.verb === 'get') {
-        prefKeys = extPrefsBranch.getChildList('');
-        prefsObj = {};
-
-        for (i = 0; i < prefKeys.length; i++) {
-          // All of our legitimate prefs should be strings, but issue #237 suggests
-          // that things may sometimes get into a bad state. We will check and delete
-          // and prefs that aren't strings.
-          // https://github.com/adam-p/markdown-here/issues/237
-          if (extPrefsBranch.getPrefType(prefKeys[i]) !== extPrefsBranch.PREF_STRING) {
-            extPrefsBranch.clearUserPref(prefKeys[i]);
-            continue;
-          }
+    var privileged, prefsBranch, prefKeys, prefsObj, i;
 
-          try {
-            if ( Services.vc.compare(Services.appinfo.platformVersion, '58') < 0 ) {
-              prefsObj[prefKeys[i]] = window.JSON.parse(
-                                        extPrefsBranch.getComplexValue(
-                                          prefKeys[i],
-                                          Components.interfaces.nsISupportsString).data);
-            } else {
-              prefsObj[prefKeys[i]] = window.JSON.parse(
-                                        extPrefsBranch.getStringPref(
-                                          prefKeys[i]));
-            }
-          }
-          catch(e) {
-            // Null values and empty strings will result in JSON exceptions
-            prefsObj[prefKeys[i]] = null;
-          }
+    privileged = (typeof(Components) !== 'undefined' && typeof(Components.classes) !== 'undefined');
+    if (!privileged) {
+      // This means that this code is being called from a content script.
+      // We need to send a request from this non-privileged context to the
+      // privileged background script.
+      data.action = 'prefs-access';
+      Utils.makeRequestToPrivilegedScript(
+        document,
+        data,
+        callback);
+
+      return;
+    }
+
+    prefsBranch = Components.classes['@mozilla.org/preferences-service;1']
+                            .getService(Components.interfaces.nsIPrefService)
+                            .getBranch('extensions.markdown-here.');
+
+    if (data.verb === 'get') {
+      prefKeys = prefsBranch.getChildList('');
+      prefsObj = {};
+
+      for (i = 0; i < prefKeys.length; i++) {
+        // All of our legitimate prefs should be strings, but issue #237 suggests
+        // that things may sometimes get into a bad state. We will check and delete
+        // and prefs that aren't strings.
+        // https://github.com/adam-p/markdown-here/issues/237
+        if (prefsBranch.getPrefType(prefKeys[i]) !== prefsBranch.PREF_STRING) {
+          prefsBranch.clearUserPref(prefKeys[i]);
+          continue;
         }
 
-        callback(prefsObj);
-        return;
+        prefsObj[prefKeys[i]] = Utils.getMozJsonPref(prefsBranch, prefKeys[i]);
       }
-      else if (data.verb === 'set') {
-        for (i in data.obj) {
-          supportString.data = window.JSON.stringify(data.obj[i]);
-          extPrefsBranch.setComplexValue(
-            i,
-            Components.interfaces.nsISupportsString,
-            supportString);
-        }
 
-        if (callback) callback();
-        return;
+      callback(prefsObj);
+      return;
+    }
+    else if (data.verb === 'set') {
+      for (i in data.obj) {
+        Utils.setMozJsonPref(prefsBranch, i, data.obj[i]);
       }
-      else if (data.verb === 'clear') {
-        if (typeof(data.obj) === 'string') {
-          data.obj = [data.obj];
-        }
 
-        for (i = 0; i < data.obj.length; i++) {
-          extPrefsBranch.clearUserPref(data.obj[i]);
-        }
+      if (callback) callback();
+      return;
+    }
+    else if (data.verb === 'clear') {
+      if (typeof(data.obj) === 'string') {
+        data.obj = [data.obj];
+      }
 
-        if (callback) return callback();
-        return;
+      for (i = 0; i < data.obj.length; i++) {
+        prefsBranch.clearUserPref(data.obj[i]);
       }
-    }
-    catch (ex) {
-      // This exception was thrown by the Components.classes stuff above, and
-      // means that this code is being called from a content script.
-      // We need to send a request from this non-privileged context to the
-      // privileged background script.
-      data.action = 'prefs-access';
-      Utils.makeRequestToPrivilegedScript(
-        document,
-        data,
-        callback);
+
+      if (callback) return callback();
+      return;
     }
   }
 };
diff --git a/src/common/utils.js b/src/common/utils.js
index 08257186..46dae091 100644
--- a/src/common/utils.js
+++ b/src/common/utils.js
@@ -659,6 +659,87 @@ function nextTickFn(callback, context) {
 }
 
 
+/*? if(platform==='thunderbird'){ */
+
+/**
+ * Returns the stored preference string for the given key.
+ * Must only be called from a privileged Mozilla script.
+ * @param {nsIPrefBranch} prefsBranch
+ * @param {string} key
+ * @returns {?string} The preference value. May be null if the preference is not set
+ * or is null.
+ */
+function getMozStringPref(prefsBranch, key) {
+  try {
+    if (Services.vc.compare(Services.appinfo.platformVersion, '58') < 0) {
+      return prefsBranch.getComplexValue(
+                          key,
+                          Components.interfaces.nsISupportsString).data;
+    }
+
+    return prefsBranch.getStringPref(key, null);
+  }
+  catch(e) {
+    // getComplexValue could have thrown an exception because it didn't find the key. As
+    // with getStringPref, we will default to null.
+    return null;
+  }
+}
+
+/**
+ * Get the stored preference object, JSON-parsed, for the given key.
+ * Must only be called from a privileged Mozilla script.
+ * @param {nsIPrefBranch} prefsBranch
+ * @param {string} key
+ * @returns {?(object|number|boolean|string)} The preference object (any valid JSON
+ * type). May be null if the preference is not set or is null.
+ */
+function getMozJsonPref(prefsBranch, key) {
+  try {
+    return JSON.parse(getMozStringPref(prefsBranch, key));
+  }
+  catch(e) {
+    return null;
+  }
+}
+
+/**
+ * Store the preference string for the given key.
+ * Must only be called from a privileged Mozilla script.
+ * @param {nsIPrefBranch} prefsBranch
+ * @param {string} key
+ * @param {string} value
+ */
+function setMozStringPref(prefsBranch, key, value) {
+  var supportString = Components.classes['@mozilla.org/supports-string;1']
+                        .createInstance(Components.interfaces.nsISupportsString);
+
+  if (Services.vc.compare(Services.appinfo.platformVersion, '58') < 0) {
+    supportString.data = value;
+    prefsBranch.setComplexValue(
+                  key,
+                  Components.interfaces.nsISupportsString,
+                  supportString);
+  }
+  else {
+    prefsBranch.setStringPref(key, value);
+  }
+}
+
+/**
+ * Store the given object in preferences under the given key.
+ * Must only be called from a privileged Mozilla script.
+ * @param {nsIPrefBranch} prefsBranch
+ * @param {string} key
+ * @param {?(object|number|boolean|string)} value
+ */
+function setMozJsonPref(prefsBranch, key, value) {
+  setMozStringPref(prefsBranch, key, JSON.stringify(value));
+}
+
+/*? } */
+
+
 /*
  * i18n/l10n
  */
@@ -736,7 +817,7 @@ function triggerStringBundleLoadListeners() {
 }
 
 
-// Must only be called from a priviledged Mozilla script
+// Must only be called from a privileged Mozilla script
 function getMozStringBundle() {
   if (typeof(Components) === 'undefined' || typeof(Components.classes) === 'undefined') {
     return false;
@@ -755,7 +836,7 @@ function getMozStringBundle() {
 
   // First load the English fallback strings
 
-  stringBundle = window.Components.classes["@mozilla.org/intl/stringbundle;1"]
+  stringBundle = Components.classes["@mozilla.org/intl/stringbundle;1"]
                         .getService(Components.interfaces.nsIStringBundleService)
                         // Notice the explicit locale in this path:
                         .createBundle("resource://markdown_here_locale/en/strings.properties");
@@ -768,7 +849,7 @@ function getMozStringBundle() {
 
   // Then load the strings that are overridden for the current locale
 
-  stringBundle = window.Components.classes["@mozilla.org/intl/stringbundle;1"]
+  stringBundle = Components.classes["@mozilla.org/intl/stringbundle;1"]
                         .getService(Components.interfaces.nsIStringBundleService)
                         .createBundle("chrome://markdown_here/locale/strings.properties");
 
@@ -1172,6 +1253,10 @@ Utils.getTopURL = getTopURL;
 Utils.nextTick = nextTick;
 Utils.nextTickFn = nextTickFn;
 /*? if(platform==='thunderbird'){ */
+Utils.getMozStringPref = getMozStringPref;
+Utils.getMozJsonPref = getMozJsonPref;
+Utils.setMozStringPref = setMozStringPref;
+Utils.setMozJsonPref = setMozJsonPref;
 Utils.getMozStringBundle = getMozStringBundle;
 /*? } */
 /*? if(platform==='safari'){ */
diff --git a/src/firefox/chrome/content/background-services.js b/src/firefox/chrome/content/background-services.js
index 75270803..6eec8d95 100644
--- a/src/firefox/chrome/content/background-services.js
+++ b/src/firefox/chrome/content/background-services.js
@@ -126,16 +126,14 @@ true); // wantsUntrusted -- needed for communication with content scripts
 
 // Access the actual Firefox/Thunderbird stored prefs.
 function prefsAccessRequestHandler(request) {
-  var extPrefsBranch, supportString, prefKeys, prefsObj, i;
+  var prefsBranch, prefKeys, prefsObj, i;
 
-  extPrefsBranch = Components.classes['@mozilla.org/preferences-service;1']
+  prefsBranch = Components.classes['@mozilla.org/preferences-service;1']
                              .getService(Components.interfaces.nsIPrefService)
                              .getBranch('extensions.markdown-here.');
-  supportString = Components.classes["@mozilla.org/supports-string;1"]
-                            .createInstance(Components.interfaces.nsISupportsString);
 
   if (request.verb === 'get') {
-    prefKeys = extPrefsBranch.getChildList('');
+    prefKeys = prefsBranch.getChildList('');
     prefsObj = {};
 
     for (i = 0; i < prefKeys.length; i++) {
@@ -143,44 +141,19 @@ function prefsAccessRequestHandler(request) {
       // that things may sometimes get into a bad state. We will check and delete
       // and prefs that aren't strings.
       // https://github.com/adam-p/markdown-here/issues/237
-      if (extPrefsBranch.getPrefType(prefKeys[i]) !== extPrefsBranch.PREF_STRING) {
-        extPrefsBranch.clearUserPref(prefKeys[i]);
+      if (prefsBranch.getPrefType(prefKeys[i]) !== prefsBranch.PREF_STRING) {
+        prefsBranch.clearUserPref(prefKeys[i]);
         continue;
       }
 
-      try {
-        if ( Services.vc.compare(Services.appinfo.platformVersion, '58') < 0 ) {
-          prefsObj[prefKeys[i]] = JSON.parse(
-                                    extPrefsBranch.getComplexValue(
-                                      prefKeys[i],
-                                      Components.interfaces.nsISupportsString).data);
-        } else {
-          prefsObj[prefKeys[i]] = JSON.parse(
-                                    extPrefsBranch.getStringPref(
-                                      prefKeys[i]));
-        }
-      }
-      catch(e) {
-        // Null values and empty strings will result in JSON exceptions
-        prefsObj[prefKeys[i]] = null;
-      }
+      prefsObj[prefKeys[i]] = imports.Utils.getMozJsonPref(prefsBranch, prefKeys[i]);
     }
 
     return prefsObj;
   }
   else if (request.verb === 'set') {
     for (var key in request.obj) {
-      supportString.data = JSON.stringify(request.obj[key]);
-      if ( Services.vc.compare(Services.appinfo.platformVersion, '58') < 0 ) {
-        extPrefsBranch.setComplexValue(
-          key,
-          Components.interfaces.nsISupportsString,
-          supportString);
-      } else {
-        extPrefsBranch.setStringPref(
-          key,
-          supportString.data);
-      }
+      imports.Utils.setMozJsonPref(prefsBranch, key, request.obj[key]);
     }
 
     return;
@@ -191,7 +164,7 @@ function prefsAccessRequestHandler(request) {
     }
 
     for (i = 0; i < request.obj.length; i++) {
-      extPrefsBranch.clearUserPref(request.obj[i]);
+      prefsBranch.clearUserPref(request.obj[i]);
     }
 
     return;
@@ -230,54 +203,18 @@ catch (ex) {
 function updateHandler(currVer) {
   var prefService = Components.classes['@mozilla.org/preferences-service;1']
                               .getService(Components.interfaces.nsIPrefService);
-  var extPrefsBranch = prefService.getBranch('extensions.markdown-here.');
+  var prefsBranch = prefService.getBranch('extensions.markdown-here.');
   var extSyncBranch = prefService.getBranch('services.sync.prefs.sync.extensions.markdown-here.');
-  var supportString = Components.classes["@mozilla.org/supports-string;1"]
-                                .createInstance(Components.interfaces.nsISupportsString);
-
-  var lastVersion = '';
-  try {
-    if ( Services.vc.compare(Services.appinfo.platformVersion, '58') < 0 ) {
-        lastVersion = JSON.parse(
-                        extPrefsBranch.getComplexValue(
-                          'last-version',
-                          Components.interfaces.nsISupportsString).data);
-    } else {
-        lastVersion = JSON.parse(
-                        extPrefsBranch.getStringPref(
-                          'last-version'));
-    }
-  }
-  catch (ex) {
-  }
+
+  var lastVersion = imports.Utils.getMozJsonPref(prefsBranch, 'last-version');
 
   // The presence of this pref indicates that it's not the first run.
-  var localFirstRun = !extPrefsBranch.prefHasUserValue('local-first-run');
-
-  supportString.data = JSON.stringify(false);
-  if ( Services.vc.compare(Services.appinfo.platformVersion, '58') < 0 ) {
-    extPrefsBranch.setComplexValue(
-      'local-first-run',
-      Components.interfaces.nsISupportsString,
-      supportString);
-  } else {
-    extPrefsBranch.setStringPref(
-      'local-first-run',
-      supportString.data);
-  }
+  var localFirstRun = !prefsBranch.prefHasUserValue('local-first-run');
+
+  imports.Utils.setMozJsonPref(prefsBranch, 'local-first-run', false);
 
   if (currVer !== lastVersion) {
-    supportString.data = JSON.stringify(currVer);
-    if ( Services.vc.compare(Services.appinfo.platformVersion, '58') < 0 ) {
-      extPrefsBranch.setComplexValue(
-        'last-version',
-        Components.interfaces.nsISupportsString,
-        supportString);
-    } else {
-      extPrefsBranch.setStringPref(
-        'last-version',
-        supportString.data);
-    }
+    imports.Utils.setMozJsonPref(prefsBranch, 'last-version', currVer);
 
     // Set the preference sync flags while we're at it.
 
diff --git a/src/install.rdf b/src/install.rdf
index cab41794..ec2d3044 100644
--- a/src/install.rdf
+++ b/src/install.rdf
@@ -30,7 +30,7 @@
           <Description>
             <em:id>toolkit@mozilla.org</em:id>
             <em:minVersion>6.0</em:minVersion>
-            <em:maxVersion>54.*</em:maxVersion>
+            <em:maxVersion>60.*</em:maxVersion>
           </Description>
         </em:targetApplication>
 
@@ -152,7 +152,8 @@
         <em:iconURL>resource://markdown_here_common/images/icon128.png</em:iconURL>
         <em:homepageURL>https://github.com/adam-p/markdown-here</em:homepageURL>
 
-        <em:optionsURL>chrome://markdown_here/content/options.xul</em:optionsURL>
+        <em:optionsType>3</em:optionsType>
+        <em:optionsURL>resource://markdown_here_common/options.html</em:optionsURL>
 
     </Description>
 </RDF>