Minimum camera spec required.

I am curious to hear peoples views on what camera hardware is considered “minimum spec” for producing successful stock photos for sale on sites such as Shutterstock and Fotolia.

Much of my collections were uploading many years ago and photographed on camera’s that are now considered to be old. – Some of these photos still sell really well but I imagine if they were uploaded these days they would be rejected on quality or resolution¬† grounds.