Hi mah,
Can you please refer the following SAP Note and check whether it helps you:
1322923 - Maintenance strategy / deadlines BW Business Explorer (BEx)
This SAP Note 1322923 gives the maintenance strategy / deadlines BW Business Explorer (BEx)
Please refer this SAP Note for details.
Also, please refer the following SAP Note:
147519 - Maintenance strategy / deadlines for SAP GUI
Thanks & Regards,
Sapna