The supported environment pages list the softwares that are supported with different IBM Cognos products. These are the links that you should look for when you are planning a new install or need to check the different softwares that can work in tandem with IBM Cognos products.
Link to Supported Environment page for Cognos products -
These links only list the current supported versions for IBM Cognos products. For example, you will find only the latest versions under IBM Cognos 8 BI : 8.3, 8.4 and 8.4.1.