There are some people who are just starting to learn more about investments and one of the things that they will come across is KIM also known as Key Information Memorandum. It is not true that this would need to update every 6 months. Rather, you just need to make some changes to it if you believe that some of the information that is placed in this document is not true anymore.
The KIM will have more detailed information regarding the scheme that you want to invest on. It can actually help you decide if this is an investment that is worth pushing or not. There are some details in KIM that you can also see in SAI and SID.