Nullsoft purposely went from Winamp 3 to 5

Nullsoft purposely went from Winamp 3 to 5 because?

WinAMP 0.92

was first released in 1997, when Justin Frankel and Dmitry Boldyrev, formerly students at the University of Utah, integrated their Windows user interface with the Advanced Multimedia Products “AMP (MP3 Technology)” MP3 file playback engine. The minimalist the 0.20a was released as freeware on 21 April 1997. Its windowless menubar-only interface showed only play (open), stop, pause, and unpause functions. A file specified on the command line or dropped onto its icon would be played. MP3 decoding was performed by the AMP decoding engine developed by Advanced Multimedia Products co-founder Tomislav Uzelac, which was free for non-commercial use.

WinAMP 0.92 was released as a freeware in May 1997. Within the standard Windows frame and menubar, it had the beginnings of the “classic” GUI: dark gray rectangle with silver 3D-effect transport buttons, a red/green volume slider, time displayed in a green LED font, with trackname, MP3 bitrate and “mixrate” in green. There was no position bar, and a blank space where the spectrum analyzer and waveform analyzer would later appear. Multiple files on the command line or dropped onto its icon were enqueued in the playlist.

Winamp 1

Version 1.006 was released June 7, 1997 ┬árenamed “Winamp” (lower case). It showed a spectrum analyzer, and color changing volume slider, but no waveform display. The AMP non-commercial license was included in its help menu.
According to Tomislav Uzelac, Frankel licensed the AMP 0.7 engine June 1, 1997. Frankel formally founded Nullsoft Inc. in January 1998 and continued development of Winamp, which changed from freeware to $10 shareware. In March, Uzelac’s company, Advanced Multimedia Products (which by then had been merged into PlayMedia Systems), sent a cease-and-desist letter to Nullsoft, claiming unlawful use of AMP. Nullsoft responded that they had replaced AMP with Nitrane, Nullsoft’s proprietary decoder, but Playmedia disputed this.[citation needed]
Version 1.90, released March 31, 1998 was the first release as a general-purpose audio player, and documented on the website as supporting plugins, of which it included two input plugins (MOD and MP3) and a visualization plugin. The installer for Version 1.91, released 18 days later, included wave, cdda, and Windows tray handling plugins, as well as the famous Wesley Willis-inspired DEMO.MP3 file “Winamp, it really whips the llama’s ass”.
By July 1998, Winamp’s various versions had been downloaded over three million times.

Winamp 2

2.0 was released on September 8, 1998. The 2.x versions were widely used and made Winamp one of the most downloaded pieces of software for Windows. The new version improved the usability of the playlist, made the equalizer more accurate, introduced more plug-ins and allowed skins for the playlist and equalizer windows.
PlayMedia filed a federal lawsuit against Nullsoft in March 1999. In May, 1999, PlayMedia was granted an injunction by Federal Judge A. Howard Matz against distribution of Nitrane by Nullsoft, and the same month the lawsuit was settled out-of-court with licensing and confidentiality agreements.[38] Soon after, Nullsoft switched to an ISO decoder from the Fraunhofer Gesellschaft, the developers of the MP3 format.
Winamp 2.10, released March 24, 1999 included a new version of the “Llama” demo.mp3 featuring a musical sting and bleating.
Nullsoft was bought by AOL in June 1999 for US$80 million in stock.
Nullsoft relaunched the Winamp-specific winamp.com in December 1999 to provide easier access to skins, plug-ins, streaming audio, song downloads, forums and developer resources.
As of June 22, 2000 Winamp “surpassed 25 million registrants”.

Winamp3

The next major version, Winamp3 (so spelled to include mp3 in the name and to mark its separation from the Winamp 2 codebase), was released on August 9, 2002. It was a complete rewrite of version 2, newly based on the Wasabi application framework, which offered additional functionality and flexibility. Winamp3 was developed parallel to Winamp 2, but “many users found it consumed too many system resources and was unstable (or even lacked some valued functionality, such as the ability to count or find the total duration of tracks in a playlist)”. Winamp3 had no backward compatibility with Winamp 2 skins and plugins, and the SHOUTcast sourcing plugin was not supported. No Winamp3 version of SHOUTcast was ever released.
In response to users reverting to Winamp 2, Nullsoft continued the development of Winamp 2 to versions 2.9 and 2.91 in 2003,[50] even alluding to it humorously.[51] The beta versions 2.92 and 2.95 were released with the inclusion of some of the functionality of the upcoming Winamp 5. During this period the Wasabi cross-platform application framework and skinnable GUI toolkit was derived from parts of the Winamp3 source code. For Linux, Nullsoft released an alpha version of Winamp3 on October 9, 2001 but has not updated it despite continued user interest.[52]

Winamp 5

The Winamp 2 and Winamp3 branches were later fused into Winamp 5. Nullsoft joked that “nobody wants to see a Winamp 4 skin” (‘4 skin’ being a pun on foreskin).[53] It was also joked that “Winamp 5 is so good they skipped a number” and “Winamp 2+3=5,”.[54] 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.
From version 5.2 onwards, support for synchronizing with an iPod is built-in.