RSS was first invented by Netscape. They wanted to use an XML format to distribute news, stories, and information. Netscape refined the version of RSS and then dropped it.
Later Userland Software started controlling RSS specifications and releasing newer RSS versions. They continued development of their own version of RSS and eventually UserLand released RSS v2.
RSS has been released in many different versions.
12/27/97 - Dave Winer at Userland developed scriptingNews. RSS was born.
3/15/99 - Netscape developed RSS 0.90 (which supported scriptingNews). This was simply XML with an RDF Header and it was used for my.netscape.com.
6/15/99 - Dave Winer at UserLand develops scriptingNews 2.0b1, which included Netscape's RSS 0.90 features also.
7/10/99 - Netscape developed RSS 0.91. In this version they removed the RDF header, but included most features from scriptingNews 2.0b1.
7/28/99 - UserLand deprecated scriptingNews formats and adopted only RSS 0.91.
Netscape stops their RSS development.
6/4/00 - UserLand releases the official RSS 0.91 specification.
8/14/00 - A group led by Rael Dornfest at O'Reilly, developed RSS 1.0. This format uses RDF and namespaces. This version is often confused as being a new version of 0.91, but this is a completely new format with no ties to RSS 0.91
12/25/00 - Dave Winer at UserLand develops RSS 0.92, which is 0.91 with optional elements.
04/20/01 - RSS0.93 was discussed but never deployed.
03/14/02 - MetaWeblog API merged RSS 0.92 with XML-RPC to provide a powerful blogging API.
09/18/02 - Dave Winer developed RSS 2.0 after leaving Userland. This is 0.92 with optional elements. MetaWeblog API updated for RSS 2.0. While in development, this format was called 0.94.
07/15/03 - Official Spec RSS 2.0 was released through Harvard under a Creative Commons license.
There is no consensus on using RSS Feed version. It's up to you, which version you want to use. We would suggest to use the latest one, which is RSS2.0. This is simple enough to use and easy to learn.
We will see Feed formats for these versions in the next chapter.