Currently it asks which version introduced the problem, but users are unlikely to know if they don't update and test every single version released, and this field is rarely filled in practice by non-developers. On the other hand, it's much easier to recall the last working version that they have used before. So ask for the last known working version, which is useful information for developers to narrow down bisecting range. Also ask when did the issue start in general since the issue can be caused by system or driver updates.