The Winamp 2 and Winamp3 branches were later fused into Winamp 5 — Nullsoft justified their non-sequential christening by quipping that 2 + 3 = 5 — taking the best parts from both applications. They also joked that "nobody wants to see a Winamp 4 skin" ('4 skin' being a pun on foreskin). Winamp 5 was based on the Winamp 2 codebase, with several Winamp3 features (e.g. modern skins) incorporated. Winamp 5.0 was released in December 2003. Most of the Wasabi framework built for creating Winamp3 and its components was released as open source, and as of 2005 an active development effort has succeeded in making a standalone version of Wasabi, minus the skinning and scripting modules which were never released.
Winamp 5 comes in three versions. Lite and Full are freeware, and Pro requires registration and (as of October, 2007) sells for US$19.95. The Lite version has far less functionality (largely supplementable with plugins) while still replicating most of Winamp 2's feature set in a far smaller installer. The Full version offers a richer feature set, including music ripping and CD burning at limited speeds (6x for ripping and 2x for burning). The Pro version features unlimited speed music ripping and CD burning and MP3 encoding.
From version 5.2 on, support for synchronizing iPods is built-in.
Winamp 5.5: 10th Anniversary Edition, released on October 10, 2007, marked the tenth year since the first release of Winamp. A beta preview was released on September 10, 2007. New features to the player included album art support, a much improved localization support (with several official, localized Winamp releases, such as German's, Polish's and French's), and a unified player and media library interface skin. This version also dropped support for Windows 9x.