Green damsons?

[Mibby]

Ive just got some damsons from the local city farm, got them home and theyre mostly greeny purple and hard rather than dark purple and squishy lije last years. Possibly not fully ripe yet? If i cook them down and add sugar will they do for a crumble / pie or will we all get stomach ache?

Could be a different variety. But if they're very hard, they don't sound ripe. I would leave them to ripen for a day or several.