 They must be used with non-breaking spaces, preferably narrow, if available, i.e.U+202F which is present in all up-to-date general-purpose fonts, but still missing in some computer fonts from the early years of Unicode, due to the belated encoding of U+202F (1999) after the flaw of not giving U+2008 non-breakable property as it was given to the related U+2007 .Legacy support of narrow non-breakable spaces was done at rendering level only, without interoperability as provided by Unicode support.