[uaxid.def.stable]

# Annex E (informative) Conformance with UAX #31 [[uaxid]](./#uaxid)

## E.2 R1 Default identifiers [[uaxid.def]](uaxid.def#stable)

### E.2.2 R1b Stable identifiers [uaxid.def.stable]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/uax31.tex#L53)

An implementation of UAX #31 may choose to guarantee
that identifiers are stable across versions of the Unicode Standard[.](#1.sentence-1)

Once a string qualifies as an identifier it does so in all future versions[.](#1.sentence-2)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/uax31.tex#L58)

C++ does not make this guarantee,
except to the extent that UAX #31 guarantees
the stability of the XID_Start and XID_Continue properties[.](#2.sentence-1)