Any progress here?

I still cannot reproduce.

Unfortunately this report is still valid.

If it's related to the %a specifier, is this fixed now with the fixes 
for bug 11831?

It's triggered by the "%a" format specifier again.
If I remove that from the "date_format" pref, it renders fine.

I've added this debug code to the Form renderer:

--- a/framework/Form/lib/Horde/Form/Type.php
+++ b/framework/Form/lib/Horde/Form/Type.php
@@ -2968,6 +2968,12 @@ class Horde_Form_Type_monthdayyear extends 
Horde_Form_Type {
              $date = $this->getDateOb($date);
          }

+        $fp = fopen("/tmp/tomj_dateformat.log", "a");
+        fprintf($fp, print_r($date,true)."\n");
+        fprintf($fp, "%s",print_r($this,true)."\n");
+        fprintf($fp, "strftime result: 
".$date->strftime($this->_format_out)."\n");
+        fclose($fp);
+
          return $date->strftime($this->_format_out);
      }

Output:
Horde_Date Object
(
     [_year:protected] => 1900
     [_month:protected] => 1
     [_mday:protected] => 1
     [_hour:protected] => 0
     [_min:protected] => 0
     [_sec:protected] => 0
     [_timezone:protected] => Europe/Berlin
     [_defaultFormat:protected] => Y-m-d H:i:s
     [_formatCache:protected] => Array
         (
         )

)

Horde_Form_Type_monthdayyear Object
(
     [_start_year] => 1900
     [_end_year] => 2022
     [_picker] => 1
     [_format_in] => %Y-%m-%d
     [_format_out] => %a, %d.%m.%Y
)

strftime result: Thu, 07.02.2036


-> It looks like Horde_Date->strftime() messes up.

Cannot reproduce.

Hi,

when one creates a new contact with an anniversary day of 06.12.1900,
it is shown later on as 11.01.2037 in turba. Same for the year 1901.
Everything works correctly starting 1902.

Funnily kronolith shows the correct anniversary when using 1900.

Cheers,
Thomas