Was it by 'auto-renew'? If yes, it seems to be that the World sub is still offered to existing subscribers if they auto renew, so you are safe for now.
I can't use auto renew (long story, due to FindMyPast messing up my sub last year), though, and they want me to let my subscription lapse on renewal date, then take out a new subscription (including a code they have provided for a discount I was entitled to), but if I do this, I have to choose between the new package titles, and despite FindMyPast saying the higher of the two gives me exact same access to the World/Premium level sub I currently have, the description of the new packages doesn't read as if it does.
My other option, I suppose, is to let my current World/Premium sub auto-renew, and then try to get them to refund me the difference between the renewal price advised to me and the actual price I am due to pay with the discount code they supplied, but they are insisting I can do it the way they have suggested (let renewal lapse then start new subscription on new name package), so are unlikely to agree.
I just can't help but feel the new named package isn't the same as the old World/Premium one, hence was looking to see if others have found it to be different. I don't want to find I do it the way they are suggesting and then I'm stuck with an inferior package.