diff --git a/inc/well-known.php b/inc/well-known.php
index 0721a630..e26850ad 100644
--- a/inc/well-known.php
+++ b/inc/well-known.php
@@ -95,8 +95,8 @@ function ischedule_get ( )
         <scheme>mailto</scheme>
       </supported-recipient-uri-scheme-set>
       <max-content-length>102400</max-content-length>
-      <min-date-time>19910101T000000Z</min-date-time>
-      <max-date-time>20381231T000000Z</max-date-time>
+      <min-date-time>00010101T000000Z</min-date-time>
+      <max-date-time>99991231T000000Z</max-date-time>
       <max-instances>150</max-instances>
       <max-recipients>250</max-recipients>