Macromedia Flash Player 4: First player with a full scripting implementation (called Actions). The scripting was a flash based syntax and contained support for loops, conditionals, variables and other basic language constructs.
Macromedia Flash Player 6: Added an event handling model, accessibility controls and support for switch. The first version with support for the AMF and RTMP protocols which allowed for on demand audio/video streaming.
Adobe Flash Player 9 (initially called 8.5): Added ActionScript 3.0 with the advent of a new virtual machine, called ActionScript Virtual Machine 2 (AVM2), which coexists with the previous AVM1 needed to support legacy content. Performance increases were a major objective for this release of the player including a new JIT compiler. Support for binary sockets, E4X XML parsing, full-screen mode and Regular Expressions were added. This is the first release of the player to be titled Adobe Flash Player.
Adobe Flash Player 10 (code named "Astro"): Added basic 3D manipulation, such as rotating on the X, Y, and Z axis, a 3D drawing API, and texture mapping. Ability to create custom filters using Adobe Pixel Bender. Several visual processing tasks are now offloaded to the GPU which gives a noticeable decrease to rendering time for each frame, resulting in higher frame rates, especially with H.264 video. There is a new sound API which allows for custom creation of audio in flash, something that has never been possible before. Furthermore, Flash Player 10 supports Peer to Peer (P2P) communication with Real Time Media Flow Protocol (RTMFP).
Adobe Flash Player 11: The major addition in this version are advanced (graphic card accelerated) 3D capabilities for Windows Desktop, Mac Desktop, iOS, Android, and other major platforms. Significant compatibility improvements have been added for the iOS platform, and other non-desktop platforms. Other features include H.264 encoding for cameras, Native JSON support, Cubic Bézier Curves, a secure random number generator, LZMA compression for swf files, workers to offload some code execution to other processor threads, graphics card accelerated camera feed rendering, memory intrinsics and performance analysis, and the ActionScript Compiler 2.0, as well as some other minor additions.