I wouldn’t be worried. It can take up to 10 days after the changelog is published. The minimum allowed version is currently v1.9.0, and you will see a notification in your web dashboard if your node is running an old version past the expected date. You can force an update if you want, but then you won’t know if watchtower is working properly. If your node isn’t updated by Sept 19th, then I would start looking for problems.
I was looking this post earlier and finally found it: