Why is my Pantone swatch labelled ‘revised standard’?

Why is my Pantone swatch labelled revised standard, have they changed the colour?

Revised Standard means that the dye recipe has changed since the colour was first established; it may not have been recently. The colour will still match the original colour standard under D65.

The first Pantone TCX colours were formulated in 2007 these 1925 colours are still in the range, however dyeing technology has changed since and some dyes are no longer available.

The recipes of some colours were changed in response to customer demand, to make them more reproducible in the real world and to reduce problems achieving the colour. Pantone has worked closely with a number of dyeing mills to optimise colour matching, where difficulty remained the decision was made to reformulate the colour.

It does not mean that the actual colour swatch has changed as the revised recipe is formulated to match the original colour perfectly under D65 daylight lighting. The swatches are marked up to alert you to the possibility that the colour may be slightly different under another light source (metameric).