Strictly speaking, Facter is an autonomous software project and does not follow Puppet's versioning and release schedule. It is not a surprise, therefore, that Facter 2 was released more or less when Puppet 3.5 was already out.
Note
The first official version of Facter 2 is 2.0.1.
Version 2.0.0 was skipped because previously some 2.0.0.rcX release candidate versions, based on older and deprecated code, were released, and the guys at Puppet Labs preferred to avoid confusion, since the code in 2.0.1 is totally new and unrelated to the one in 2.0.0.rcX.
The main features of Facter 2 (http://docs.puppetlabs.com/facter/2.0/) are:
New return types: In Facter 1, all facts were simple strings. Now, facts values can be expressed in different data types, such as
Integer,Float,TrueClass,FalseClass,NilClass,String,Array, andHash.Structured facts: Facts can have complex structures and represent data with arrays or hashes. This greatly enhances their power and expressiveness.
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