Update 1.1 includes a modification to the Search service to make it more secure. This change is also in TFS 2018 Update 3. With this change, HTTP Basic authentication is enabled on the communication between the TFS and Search services to make it more secure. Any user installing or upgrading to TFS 2018 Update 1.1 or TFS 2018 Update 3 will need to provide a user name/password while configuring Search (and also during Search service setup in case of remote Search service). Basic auth is not a replacement for channel encryption. If the connection between TFS and Search service is secured using IPSec encryption (or any similar means) we recommend continuing to do so. This blog post has more information.
We recommend that all customers on TFS 2018 RTW or Update 1 upgrade to either Update 1.1 or Update 3 and we recommend customers on TFS 2018 Update 2 upgrade to Update 3 to get this improved security.
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