By Eric Simenel
This tech note addresses the problems that you may face when attempting to downgrade from AIR version 20 to an older AIR version. Prior to AIR version 20, AIR was provided as a 32-bit Runtime dynamic Library for Mac OS X. However, with the release of AIR 20, only a 64-bit Runtime dynamic Library is provided on Mac OS X. See AIR 20 release notes for details.
Certain users who are running apps that require 32-bit ANEs may want to downgrade to a lower AIR version that supports a 32-bit Runtime dynamic Library. Prior to AIR 20, downgrading AIR to a previous version (let’s say AIR 19) is a simple process:
- Download AIR 19 runtime. For downloading any other versions, see Archived Adobe AIR SDK versions.
- Uninstall AIR 20 runtime. See Removing Adobe AIR for details.
- Install AIR 19 runtime. See Installing Adobe AIR for details.
- Run AIR Settings manager utility to disable further updates of the runtime.
However, these steps will not suffice when you are downgrading from AIR 20 to a previous AIR version as there are some additional steps required in this case. To meet this requirement, the additional steps or the solutions are explained below.
Downgrading from AIR 20
Starting with AIR 20, which is a now 64-bit Runtime (instead of the previous 32 bit AIR runtime), the process for downgrading is the same as mentioned above. But there are certain points, which require attention when attempting to downgrade.
After you install AIR 20, any previously installed AIR app using the Shared Runtime that is launched gets updated. So the app’s launcher code will now be a 64-bit binary. The previously used 32-bit launcher gets renamed with a ‘_32’ suffix.
Note: AIR Captive Runtime Apps are unaffected by this upgrade to AIR 20. See AIR 64-bit on Mac OS X for more details.
If you go back to a previous AIR version, for example, AIR 19, then after uninstalling AIR 20 and installing AIR 19, an attempt to launch the updated AIR app fails because the new 64-bit launcher is unable to find the 64-bit AIR Runtime.
This problem occurs only when attempting to downgrade to an older version.
You can use either of the three solutions to resolve this issue:
Solution 1: Move the application to the Trash, empty the Trash, and reinstall it from its .air package or custom installer as you did when you installed it the first time.
Solution 2: Rename the launchers at <AIR application>/Contents/MacOS/.
- For the launcher with no suffix, add a ‘_64’ suffix.
- For the launcher with the ‘_32’ suffix, remove this suffix.
Note: Here launcher refers to the name of your <AIR application>.
Solution 3: Edit the contents of the info.plist file so that its CFBundleExecutable key has the ‘_32’ suffix. The info.plist file is present at <AIR application>/Contents/.
Downgrading after an initial AIR 20 installation from a SideCar
There is another issue that a few users may face — specifically, those who install an AIR application with a SideCar AIR 20 installation; having never before installed an AIR shared runtime and then downgrading from AIR 20.
Note: An AIR SideCar Installation is one where an .air package is distributed alongside the AIR installer so that both AIR and this application are installed at the same time.
After an Initial AIR 20 installation from a SideCar, launching the .air package results in Mac OS X “blessing” the Adobe AIR Installer that sits next to it. Hence forward, Mac OS X remembers this application as the default launcher for an .air package. If you do not delete this directory after installing, then anytime you launch an .air package, this Adobe AIR Installer is launched. Checking that the AIR Runtime is now present, it goes on with the standard AIR App installation that is done by the AIR Runtime.
Now when you uninstall AIR 20, install AIR 19, and then try to launch an .air package, this attempt fails because the Adobe AIR Installer that is a 64-bit binary is unable to load the AIR Runtime that is now a 32-bit binary again. That Adobe AIR Installer (version 20) keeps its precedence over the Adobe AIR Application Installer (version 19) that is present at /Applications/Utilities because the Adobe AIR Application Installer has not been launched yet and is “invisible” to Mac OS X.
The solution to this issue is to simply delete the directory that contains the SideCar .air package and Adobe AIR Installer so that this 64-bit binary longer exists. Thus, it will not be launched by Mac OS X when .air launches. Instead, the 32-bit Adobe AIR Application Installer will be launched.