If you are unaware it is important that AutoCAD Plant 3D Collaboration users apply this Hotfix. This is important because without the Hotfix Collaboration for Plant 3D projects will be inaccessible unless Hotfix is applied by October 31st, 2018.
Autodesk AutoCAD 2016-2019 Internet Security Hotfix & Readme
Autodesk® AutoCAD® 2019 Internet Security Hotfix
Autodesk® AutoCAD® 2018 Internet Security Hotfix
Autodesk® AutoCAD® 2017 Internet Security Hotfix
Autodesk® AutoCAD® 2016 Internet Security Hotfix
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