We are in the process of migrating all Bitbucket repositories to this new webhook, there should be no intervention needed on your end.
It can take a few hours for all repositories to be updated. If you would like to make this change yourself, simply add a webhook pointing to https://scrutinizer-ci.com/bitbucket-callback that sends the repo:push, pullrequested:created and pullrequest:updated events.
Posted Aug 01, 2018 - 12:21 CEST
Update
If your Bitbucket project is affected by this, you can now also set-up a webhook on Bitbucket instead of using a service. The webhook should point to the same endpoint at https://scrutinizer-ci.com/bitbucket-callback