diff --git a/CHANGELOG.md b/CHANGELOG.md
index 880fe83..e93a1eb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+2022.05.16
+- require Dotclear 2.22
+- fix period dates
+
 2022.04.27
 - require Dotclear 2.21.3
 - fix browser date picker
diff --git a/README.md b/README.md
index 6163216..c94acf2 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ and they will be publish ones after the others every week.
 
   * admin permissions to configure plugin
   * usage,contentadmin permissions to link feeds
-  * Dotclear 2.21.3
+  * Dotclear 2.22
 
 ## NOTICE
 
diff --git a/_define.php b/_define.php
index c2f5636..8b9034d 100644
--- a/_define.php
+++ b/_define.php
@@ -19,9 +19,9 @@ $this->registerModule(
     'Periodical',
     'Published periodically entries',
     'Jean-Christian Denis and contributors',
-    '2022.04.27',
+    '2022.05.16',
     [
-        'requires'    => [['core', '2.21']],
+        'requires'    => [['core', '2.22']],
         'permissions' => 'usage,contentadmin',
         'type'        => 'plugin',
         'support'     => 'https://github.com/JcDenis/periodical',
diff --git a/_install.php b/_install.php
index f45f0c0..9a03831 100644
--- a/_install.php
+++ b/_install.php
@@ -15,7 +15,7 @@ if (!defined('DC_CONTEXT_ADMIN')) {
     return null;
 }
 
-$dc_min = '2.21';
+$dc_min = '2.22';
 $new_version = $core->plugins->moduleInfo('periodical', 'version');
 $old_version = $core->getVersion('periodical');
 
diff --git a/dcstore.xml b/dcstore.xml
index 62c3222..0201286 100644
--- a/dcstore.xml
+++ b/dcstore.xml
@@ -1,11 +1,11 @@
 <modules xmlns:da="http://dotaddict.org/da/">
 <module id="periodical">
 <name>Periodical</name>
-<version>2022.04.27</version>
+<version>2022.05.16</version>
 <author>Jean-Christian Denis and contributors</author>
 <desc>Published periodically entries</desc>
-<file>https://github.com/JcDenis/periodical/releases/download/v2022.04.27/plugin-periodical.zip</file>
-<da:dcmin>2.21</da:dcmin>
+<file>https://github.com/JcDenis/periodical/releases/download/v2022.05.16/plugin-periodical.zip</file>
+<da:dcmin>2.22</da:dcmin>
 <da:details>https://plugins.dotaddict.org/dc2/details/periodical</da:details>
 <da:support>https://github.com/JcDenis/periodical</da:support>
 </module>
diff --git a/inc/index.period.php b/inc/index.period.php
index dbc72ae..c367877 100644
--- a/inc/index.period.php
+++ b/inc/index.period.php
@@ -30,8 +30,10 @@ $period_id      = null;
 $period_title   = __('One post per day');
 $period_pub_nb  = 1;
 $period_pub_int = 'day';
-$period_curdt   = time();
-$period_enddt   = time() + 31536000; //one year
+$period_curdt   = date('Y-m-d H:i', time());
+$period_enddt   = date('Y-m-d H:i', time() + 31536000); //one year
+$bad_period_curdt = false;
+$bad_period_enddt = false;
 
 # Get period
 if (!empty($_REQUEST['period_id'])) {
@@ -46,8 +48,8 @@ if (!empty($_REQUEST['period_id'])) {
         $period_title   = $rs->periodical_title;
         $period_pub_nb  = $rs->periodical_pub_nb;
         $period_pub_int = $rs->periodical_pub_int;
-        $period_curdt   = strtotime($rs->periodical_curdt);
-        $period_enddt   = strtotime($rs->periodical_enddt);
+        $period_curdt   = date('Y-m-d H:i', strtotime($rs->periodical_curdt));
+        $period_enddt   = date('Y-m-d H:i', strtotime($rs->periodical_enddt));
     }
 }
 
@@ -66,10 +68,30 @@ if ($action == 'setperiod') {
         $period_pub_int = $_POST['period_pub_int'];
     }
     if (!empty($_POST['period_curdt'])) {
-        $period_curdt = strtotime($_POST['period_curdt']);
+        try {
+            $period_curdt = strtotime($_POST['period_curdt']);
+            if ($period_curdt == false || $period_curdt == -1) {
+                $bad_period_curdt = true;
+
+                throw new Exception(__('Invalid date'));
+            }
+            $period_curdt = date('Y-m-d H:i', $period_curdt);
+        } catch (Exception $e) {
+            $core->error->add($e->getMessage());
+        }
     }
     if (!empty($_POST['period_enddt'])) {
-        $period_enddt = strtotime($_POST['period_enddt']);
+        try {
+            $period_enddt = strtotime($_POST['period_enddt']);
+            if ($period_enddt == false || $period_enddt == -1) {
+                $bad_period_enddt = true;
+
+                throw new Exception(__('Invalid date'));
+            }
+            $period_enddt = date('Y-m-d H:i', $period_enddt);
+        } catch (Exception $e) {
+            $core->error->add($e->getMessage());
+        }
     }
 
     # Check period title and dates
@@ -249,13 +271,13 @@ form::field('period_title', 60, 255, html::escapeHTML($period_title), 'maximal')
 <p><label for="period_curdt">' . __('Next update:') . '</label>' .
 form::datetime('period_curdt', [
     'default' => html::escapeHTML(dt::str('%Y-%m-%dT%H:%M', strtotime($period_curdt))),
-    'class'   => (!$period_curdt ? 'invalid' : ''),
+    'class'   => ($bad_period_curdt ? 'invalid' : ''),
 ]) . '</p>
 
 <p><label for="period_enddt">' . __('End date:') . '</label>' .
 form::datetime('period_enddt', [
     'default' => html::escapeHTML(dt::str('%Y-%m-%dT%H:%M', strtotime($period_enddt))),
-    'class'   => (!$period_enddt ? 'invalid' : ''),
+    'class'   => ($bad_period_enddt ? 'invalid' : ''),
 ]) .'</p>
 
 </div><div class="two-boxes">