The System Handheld Software is the operating system and the built-in applications that work on this device to let you interact with it.

It is the BlackBerry operating system, the Phone, Address Book, Messages and all other applications you see when you run your BlackBerry.

The System Handheld Software is developer per device series and further customized for every individual device model, which is created for every device carrier.

When a new version is released by RIM, they usually supply it to the carrier and then the carrier is responsible for providing it to the end customer.

Every BlackBerry phone comes with some system software already pre-installed on it. This is the main reason why you may not notice you actually need it.

The System Handheld Software is normally installed along with the RIM's Desktop Manager from the system CD that comes with the phone.

However, for whatever reasons - likely a programming error - there are many cases when this does not work as designed and Desktop Manager does not have a local mirror copy of the System Handheld Software of the phone connected to it.

When that happens, it can usually synchronize some basic PIM data, but it fails to add and remove applications.

Where to get the System Handheld Software

The most precise answer to this question should be given by your carrier.

Below is a table that we have assembled, with the help of our users, Google and other companies from the field, which could help in your search.
It is by no means complete, but is hopefully still better than having to wait on hold.

Asia Pacific

Europe

North America

South America