signatures changing retroactively

Hi, I've noticed recently that every time I change my signature, it changes in all my posts retroactively. So my new signature appears in all the posts I made before I even changed it! Is there any way to stop this?
Thanks a lot for your help

 

There's nothing you can do, it's standard with vBulletin.

 

You get one signature option at a time, and it's going to be live on all of your posts (other than the first few which will never show a sig). If we let people keep changing it, with old ones live on old posts, it would be absolutely impossible for us to monitor things like adult links that violate the rules, and all changes would have to be done manually - it would be a pain in the arse to put it mildly, especially in a forum this size.