PC giant Microsoft has informed its staff not to use popular chat app and competitor Slack, adding it to a list of “prohibited and discouraged technology” comprised of software and services that it does not want employees using outside of specific circumstances, Geekwire reported on Friday.

Geekwire wrote that while the list does cite the competitive rivalry between Microsoft and the other tools’ developers, the “prohibited” section specifically consists of software and services that could pose an IT security or intellectual property management risk.

Here’s the entry on Slack, per Geekwire, which says that all versions of Slack but the Enterprise Grid version “do not provide required controls” to protect Microsoft’s IPs and employees.

Microsoft advises that staff should use its internally developed Team software instead:

Slack Free, Slack Standard and Slack Plus versions do not provide required controls to properly protect Microsoft Intellectual Property (IP).

Existing users of these solutions should migrate chat history and files related to Microsoft business to Microsoft Teams, which offers the same features and integrated Office 365 apps, calling and meeting functionality.

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