If you look across the top of the www.apsim.info homepage you will see:
You will also find on the downloads page a link to the Release Notes for each version of APSIM. These Release Notes tell you what has changed since the last release of APSIM. They are helpful in seeing what new features have been added and what bugs have been fixed since the last release of APSIM. This will help you decide if you want to download the latest version or perhaps wait until the next release.
Products -> this contains information and downloads for other helpful products that can be used with APSIM or use APSIM that might be of interest to you. Of particular interst is the APSoil database. This is a database of APSIM soils that you may find useful for choosing a soil in your particular region. There is even a tool that will allow you to view all the soil locations in Google Earth. Click the following link for a demonstration APSoil database in Google Earth.
Documentation -> This contains the Scientific Documentation for APSIM as well some other guides and documents about APSIM.
Publications -> A list of scientific publications surrounding APSIM.
Source -> This is the source code for APSIM. APSIM has gone open source, so now you can get hold of the computer code that is used to create APSIM.
Training -> Online version of this Training Manual for APSIM.
Model Performance -> Validation graphs for various modules of APSIM. Show Experimental data versus APSIM's prediction for the same experiment.
Defects -> A link to the Bug Tracking or Feature Requesting website for APSIM. This website allows you to submit bugs or feature requests for APSIM. For more information click here