The catalogue is available as a download for A$50.00.
If you have previously purchased the catalogue (or previously held a subscription), you are able to download an updated, full version for only A$20.00 instead.
Every time there is an update to the catalogue, you will be notified, and this version is immediately available for you to purchase.
It is worth noting that purchasing an update always provides you with the complete, latest version of the catalogue, so missing an update is not a problem - the latest version always includes all previous updates.