. ▁ ▁In ▁October ▁ 2 0 0 8 ▁R DF a ▁ 1 . 0 ▁reached ▁recommendation ▁status . ▁ ▁R DF a ▁ 1 . 1 ▁reached ▁recommendation ▁status ▁in ▁June ▁ 2 0 1 2 . ▁It ▁diff ers ▁from ▁R DF a ▁ 1 . 0 ▁in ▁that ▁it ▁no ▁longer ▁re lies ▁on ▁the ▁XML - specific ▁namespace ▁mechanism . ▁Therefore , ▁it ▁is ▁possible ▁to ▁use ▁R DF a ▁ 1 . 1 ▁with ▁non - XML ▁document ▁types ▁such ▁as ▁HTML ▁ 4 ▁or ▁HTML ▁ 5 . ▁Details ▁can ▁be ▁found ▁in ▁an ▁append ix ▁to ▁HTML ▁ 5 . ▁ ▁An ▁additional ▁R DF a ▁ 1 . 1 ▁Pr imer ▁document ▁was ▁last ▁updated ▁ 1 7 ▁March ▁ 2 0 1 5 . ▁( The ▁first ▁public ▁Working ▁D raft ▁dates ▁back ▁to ▁ 1 0 ▁March ▁ 2 0 0 6 .) ▁ ▁Vers ions ▁and ▁variants ▁ ▁There ▁are ▁some ▁main ▁well - defined ▁variants ▁of ▁the ▁basic ▁concepts , ▁that ▁are ▁used ▁as ▁reference ▁and ▁as ▁abbre viation ▁to ▁the ▁W 3 C ▁standards . ▁ ▁HTML + R DF a ▁ ▁R DF a ▁was ▁defined ▁in ▁ 2 0 0 8 ▁with ▁the ▁" R DF a ▁in ▁X HTML : ▁Syntax ▁and ▁Process ing " ▁Re comm end ation . ▁Its ▁first ▁application ▁was ▁to ▁be ▁a ▁module ▁of ▁X HTML . ▁ ▁The ▁HTML ▁applications ▁remained , ▁" a ▁collection ▁of ▁attributes ▁and ▁processing ▁rules