### Summary When we receive email notifications in Outlook 2017, a little "Unsubscribe" link is available - very handy. But Outlook can't currently do anything with the unsubscribe, as it apparently needs more information. A thread on [Microsofts forums](https://social.technet.microsoft.com/Forums/office/en-US/921d45ca-c56e-4cd4-b416-f6291c1aa789/how-to-add-an-unsubscribe-link-in-email-headers-that-outlook-would-recognise?forum=outlook) indicates that Outlook might need an email address instead. [Return-Path also mentions the change in Outlook](https://blog.returnpath.com/evolution-of-list-unsubscribe/) (to the current behaviour, it seems) in this blog post. It is entirely possible this feature cannot work without an email server hooked in to Gitlab. In that case, should the `List-Unsubscribe` header even be set? The link in the bottom of emails is enough for most cases, so leaving the `List-Unsubscribe` header out might remove the bar with the option in outlook (and thus the offer to mark as junk). ### What is the current *bug* behavior? Outlook informs me it cannot unsubscribe, offers me to mark the sender as junk-mail instead. ### What is the expected *correct* behavior? Outlook magically removes me from the given subscription. ### Relevant logs and/or screenshots  ### Possible fixes (If you can, link to the line of code that might be responsible for the problem)