Does it make any difference if I publish an Adobe Air app for the 2.0 or 2.5 player? Are there any pros or cons I should consider?
Thanks. Uli
The main pro you should consider is H.264 hardware acceleration in Windows available in AIR 2.5. This is the only real automatic advantage your users would gain. There may be other under-the-hood performance benefits - both for the compiler and runtime, but they probably won't be noticeable by the user.
There are other advantages to AIR 2.5, such as StageWebView, and CSS Fonts, but unless you take advantage of those, it won't matter which player you target.
The only 'con' to targeting the newer AIR player is if your user base has not upgraded to the latest AIR runtime environment. They will be prompted (and forced) to upgrade their AIR instance in order to run your app. Given that AIR is already at version 3.1, and it prompts users to upgrade all the time, this likely is not a problem. The only time I could see this being an issue is if you are in a corporate environment with AIR as a managed package on users' systems, and they are unable to upgrade themselves. Check with a sysadmin if this is the case.