Microsoft announced plans to restrict the use of Flash, Shockwave, and Silverlight controls in Office 365. This policy changed for security reason.
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Microsoft announced its plans to block Flash, Shockwave, and Silverlight within a blog post Blocking Flash, Shockwave, Silverlight controls from activating in Office Applications for Security.
- Controls are blocked in Office 365 Monthly Channel starting in June 2018.
- Controls are blocked in Office 365 Semi Annual Targeted (SAT) Channel starting in September 2018.
- Controls are blocked in Office 365 Semi Annual (SA) Channel starting in January 2019.
Adobe itself announced the end of support for Flash by the end of 2020, and Silverlight is also projected to reach end of support in 2021. Office 2016 users are not affected. Microsoft will still allow customers to unblock the controls, as explained within this article. (via)
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