Time zone rules change

Hello, Could you please support for my request, I have a Red-hat Linux server in Egypt, I adjusted the time and date and I selected Africa/Cairo as a time zone to reflect the correct time automatically per summer, winter. The current settings of this file contain the summer/winter time change rules as the last Thursday of April, September respectively. Since the rules are changed lately by Egypt government, I need to change the predefined rules in the time zone file, but I don't know how. I found many but scattered information on the internet. So I need your help. Could you please provide me with a direct procedure to do the required task. Thank you and Best Regards, Hassan Hammad Systems Engineer