Sorry to trouble You
I I bought latest PRO version 2.0.3 and upgraded from 1.2.9
First, I did not understand where can I get or what is PRO id number.

Second after I installed new version, I get a lots of errors.
I add only 1 event, and my joomla is on local machine.
Backend errors:
Event list:
Notice: Undefined variable: eventtime in C:\wamp\www\hf_demo\administrator\components\com_icagenda\views\events\tmpl\default.php on line 168

Event edit:
Notice: Undefined variable: next in C:\wamp\www\hf_demo\administrator\components\com_icagenda\tables\event.php on line 258
Notice: Undefined variable: next in C:\wamp\www\hf_demo\administrator\components\com_icagenda\tables\event.php on line 290

Frontend errors:
Notice: Undefined index: number in C:\wamp\www\hf_demo\components\com_icagenda\helpers\icmodel.php on line 201
Notice: Undefined index: template in C:\wamp\www\hf_demo\components\com_icagenda\helpers\icmodel.php on line 218
Notice: Undefined variable: next in C:\wamp\www\hf_demo\administrator\components\com_icagenda\tables\event.php on line 290
Notice: Undefined index: number in C:\wamp\www\hf_demo\components\com_icagenda\helpers\icmodel.php on line 268
Notice: Undefined index: number in C:\wamp\www\hf_demo\components\com_icagenda\helpers\icmodel.php on line 271
Notice: Undefined index: number in C:\wamp\www\hf_demo\components\com_icagenda\helpers\icmodel.php on line 336

I added icagenda tables
Could You check it please

Seems, that also not work clean istallation of 2.0.3 to fresh Joomla 2.5.8 installation.
I have a lots of more errors in even edit:
Undefined variable: messagealert in \administrator\components\com_icagenda\views\event\tmpl\edit.php on line 73
Notice: Undefined variable: alert in \administrator\components\com_icagenda\views\event\tmpl\edit.php on line 76
Notice: Undefined property: JFormFieldModal_startdate::$class in \libraries\joomla\form\field.php on line 250
and more and more ...