you can use Outlook Filter and "Filter Rows" to avoid deleting old items from calendar.
See help topic : Advanced registry settings->Outlook Filter
SQL Filter will load only database records not older then 1 month and "Outlook Filter" will avoid GeniusConnect to delete old items originally loaded from database (also storing old items back to DB etc..).
Example Outlook Filter:
Please note:
Outlook Filter works only with Load/Store ALL, it will be ignored when selecting an Outlook Item and using the Load/Store Item button!