Users can install or update
an AIR application by double-clicking an AIR file on their computer
or from the browser (using the seamless install feature). The Adobe®
AIR® installer application manages the installation, alerting the
user if they are updating an already existing application.
However, you can also have an installed application update itself
to a new version, using the Updater class. (An installed application
may detect that a new version is available to be downloaded and
installed.) The Updater class includes an update() method
that lets you point to an AIR file on the user’s computer and update
to that version. Your application must be packaged as an AIR file
in order to use the Updater class. Applications packaged as a native
executable or package should use the update facilities provided
by the native platform.
Both the application ID and the publisher ID of an update AIR
file must match the application to be updated. The publisher ID
is derived from the signing certificate. Both the update and the
application to be updated must be signed with the same certificate.
For AIR 1.5.3 or later, the application descriptor file includes
a <publisherID> element. You must use this
element if there are versions of your application developed using
AIR 1.5.2 or earlier. For more information, see publisherID.
As of AIR 1.1 and later, you can migrate an application to use
a new code-signing certificate. Migrating an application to use
a new signature involves signing the update AIR file with both the
new and the original certificates. Certificate migration is a one-way
process. After the migration, only AIR files signed with the new
certificate (or with both certificates) will be recognized as updates
to an existing installation.
Managing updates of applications can be complicated. AIR 1.5
includes the new update framework for AdobeAIR applications. This framework provides
APIs to assist developers in providing good update capabilities
in AIR applications.
You can use certificate migration to change from a self-signed
certificate to a commercial code-signing certificate or from one
self-signed or commercial certificate to another. If you do not
migrate the certificate, existing users must remove their current
version of your application before installing the new version. For
more information see Changing certificates.
It is a good practice to include an update mechanism in your
application. If you create a new version the application, the update
mechanism can prompt the user to install the new version.
The AIR application installer creates log files when an AIR application
is installed, updated, or removed. You can consult these logs to
help determine the cause of any installation problems. See Installation logs.
New versions of the Adobe AIR runtime may include updated
versions of WebKit. An updated version of WebKit may
in unexpected changes in HTML content in a deployed AIR application.
These changes may require you to update your application. An update
mechanism can inform the user of the new version of the application.
For more information, see About the HTML environment
developers) or About the HTML environment