Adobe Flash Player 11.2 which is targeted for release in the first quarter of 2012 will be the last native version for Linux. This release include the following features:
Right and middle mouse-click support
Context menu disabling
Support for more hardware accelerated video cards (from January 2008) in order to expand availability of hardware-accelerated content.
New Throttle event API (dispatches event when Flash Player throttles, pauses, or resumes content)
Multi-threaded video decoding pipeline on the desktop which improves overall performance of video on all desktop platforms
After that version comes out sometime soon that will be the end of the road for direct Linux Flash Player support. Thereafter, the Flash Player browser plug-in for Linux will only be available via a "Pepper" implementation of Flash Player for all x86/64 platforms supported by the Google Chrome browser. Google will begin distributing this new Pepper-based Flash Player as part of Chrome on all platforms, including Linux, later this year.
Pepper is the name for the Pepper Plug-in Application Programming Interface (PPAPI). PPAPI is a cross-platform API for plug-ins for Web browsers. Pepper is currently an experimental feature of Chromium and Google Chrome. According to Adobe, "For Flash Player releases after 11.2, the Flash Player browser plug-in for Linux will only be available via the 'Pepper' API as part of the Google Chrome browser distribution and will no longer be available as a direct download from Adobe."
Adobe will also continue to support browsers using non-Pepper plug-in APIs for Flash on platforms other than Linux. This indicates that say Firefox users on Windows or Mac OS X who don't want to download the full Adobe Flash Player will still be able to use Flash within their browsers. Firefox Linux users, however, will not be able to use the up-to-date versions of Flash with Firefox, Opera, or other Web browsers.
Adobe, however, also states that it will be providing a debug player implementation of the Flash Player browser plug-in on Linux." Adobe isn't saying, yet, how this will be distributed.
What all this means for Linux desktop users is that unless you're using Chrome for your Web browser, you can pretty much forget about keeping up-to-date Adobe software. There are many open-source Flash projects and several players. The best of the Flash players, in my experience, is GNU Gnash. For PDFs, Chrome comes with a built-in PDF reader. For a standalone Linux reader for PDF, and many other document formats, I recommend KDE's Okular.