diff -ru a_send_later/chrome.manifest b_send_later/chrome.manifest
--- a_send_later/chrome.manifest	2018-03-28 08:18:42.000000000 -0400
+++ b_send_later/chrome.manifest	2018-07-30 14:31:48.000000000 -0400
@@ -3,6 +3,8 @@
 content sendlater3-datepicker chrome/content/custom-datepicker-bindings/ application={92650c4d-4b8e-4d2a-b7eb-24ecf4f6b63a}
 content sendlater3-datepicker chrome/content/custom-datepicker-bindings/ application={3550f703-e582-4d05-9a08-453d09bdfdc6} appversion<61.0
 content sendlater3-datepicker chrome/content/stock-datepicker-bindings/ application={3550f703-e582-4d05-9a08-453d09bdfdc6} appversion>=61.0
+content sendlater3-datepicker chrome/content/custom-datepicker-bindings/ application={3aa07e56-beb0-47a0-b0cb-c735edd25419} appversion<61.0
+content sendlater3-datepicker chrome/content/stock-datepicker-bindings/ application={3aa07e56-beb0-47a0-b0cb-c735edd25419} appversion>=61.0
 resource sendlater3	chrome/resource/
 locale	sendlater3	ca	chrome/locale/ca-ES/
 locale  sendlater3      cs      chrome/locale/cs-CZ/
@@ -28,10 +30,10 @@
 locale	sendlater3	tr	chrome/locale/tr-TR/
 locale	sendlater3	zh-CN	chrome/locale/zh-CN/
 locale	sendlater3	zh-TW	chrome/locale/zh-TW/
-overlay	chrome://messenger/content/messenger.xul	chrome://sendlater3/content/backgrounding.xul application={3550f703-e582-4d05-9a08-453d09bdfdc6} application={92650c4d-4b8e-4d2a-b7eb-24ecf4f6b63a}
+overlay	chrome://messenger/content/messenger.xul	chrome://sendlater3/content/backgrounding.xul application={3550f703-e582-4d05-9a08-453d09bdfdc6} application={92650c4d-4b8e-4d2a-b7eb-24ecf4f6b63a} application={3aa07e56-beb0-47a0-b0cb-c735edd25419} application={9184b6fe-4a5c-484d-8b4b-efbfccbfb514}
 overlay	chrome://messenger/content/messenger.xul	chrome://sendlater3/content/backgroundingPostbox.xul application=postbox@postbox-inc.com
-overlay	chrome://messenger/content/messenger.xul	chrome://sendlater3/content/headerView.xul application={3550f703-e582-4d05-9a08-453d09bdfdc6}
-overlay	chrome://messenger/content/messenger.xul	chrome://sendlater3/content/headerViewTB2.xul application={92650c4d-4b8e-4d2a-b7eb-24ecf4f6b63a}
+overlay	chrome://messenger/content/messenger.xul	chrome://sendlater3/content/headerView.xul application={3550f703-e582-4d05-9a08-453d09bdfdc6} application={3aa07e56-beb0-47a0-b0cb-c735edd25419}
+overlay	chrome://messenger/content/messenger.xul	chrome://sendlater3/content/headerViewTB2.xul application={92650c4d-4b8e-4d2a-b7eb-24ecf4f6b63a} application={9184b6fe-4a5c-484d-8b4b-efbfccbfb514}
 overlay	chrome://messenger/content/messenger.xul	chrome://sendlater3/content/headerViewPostbox.xul application=postbox@postbox-inc.com
 overlay chrome://messenger/content/messengercompose/messengercompose.xul chrome://sendlater3/content/composing.xul
 overlay chrome://messenger/content/messengercompose/messengercompose.xul chrome://sendlater3/content/composeToolbar.xul
diff -ru a_send_later/install.rdf b_send_later/install.rdf
--- a_send_later/install.rdf	2018-04-05 11:15:07.000000000 -0400
+++ b_send_later/install.rdf	2018-07-30 14:27:10.000000000 -0400
@@ -195,26 +195,31 @@
     <em:optionsType>3</em:optionsType>
     <em:targetApplication>
       <Description>
-        <em:id>{3550f703-e582-4d05-9a08-453d09bdfdc6}</em:id> <!-- thunderbird -->
+        <em:id>{3550f703-e582-4d05-9a08-453d09bdfdc6}</em:id> <!-- Thunderbird/FossaMail -->
         <em:minVersion>25.0a1</em:minVersion>
         <em:maxVersion>62.0</em:maxVersion>
       </Description>
     </em:targetApplication>
-    <!-- Postbox -->
-    <!--<em:targetApplication>
+    <em:targetApplication>
       <Description>
-        <em:id>postbox@postbox-inc.com</em:id>
-        <em:minVersion>3.0.6</em:minVersion>
-        <em:maxVersion>5.*</em:maxVersion>
+        <em:id>{3aa07e56-beb0-47a0-b0cb-c735edd25419}</em:id> <!-- Icedove-UXP -->
+        <em:minVersion>25.0a1</em:minVersion>
+        <em:maxVersion>52.*</em:maxVersion>
       </Description>
-    </em:targetApplication>-->
+    </em:targetApplication>
     <em:targetApplication>
-      <!-- SeaMonkey -->
       <Description>
-        <em:id>{92650c4d-4b8e-4d2a-b7eb-24ecf4f6b63a}</em:id>
+        <em:id>{92650c4d-4b8e-4d2a-b7eb-24ecf4f6b63a}</em:id> <!-- SeaMonkey -->
         <em:minVersion>2.17</em:minVersion>
         <em:maxVersion>2.53.*</em:maxVersion>
       </Description>
     </em:targetApplication>
+    <em:targetApplication>
+      <Description>
+        <em:id>{9184b6fe-4a5c-484d-8b4b-efbfccbfb514}</em:id> <!-- Iceape-UXP -->
+        <em:minVersion>2.17</em:minVersion>
+        <em:maxVersion>52.*</em:maxVersion>
+      </Description>
+    </em:targetApplication>
   </Description>
 </RDF>