[dragonwriter]

If they had left in the 'or later' clause, they couldn't use software from the third-party supplier, who only licensed under GPLv2 without the 'or later' clause.

If you are distributing someone else's software (even as part of your own work), you are restricted by the terms of the license they've given you. If that's GPLv2-only, you can't distribute a work incorporating their work as GPLv2-or-later.

[gillianseed]

With 'they' I was referring to the 'third-party' who were the ones which licenced without the 'or later' to begin with.