Docker has, what he talked about, has his cashing thing. Or if you rebuild an image and nothing's changed, an we'll just use a cash layer. And so the result is that, if you are you've set up cashing to speed things up, that cashing will insure you don't get security of bits. You need to install security up dates when you build your docker image. Apt t get up date and an up get minus y up grade. But there a problem. So debion has released a new security up date, but the dedocr image hasn't been updated - which is non ideal.