We are running an ancient and heavily modified (database) DNN 06.01.05 - I expect upgrading will be an issue.
I installed the Sep 2017 Telerik hotfix and the site is working, although when I try to add a new page I get the following exception.
A critical error has occurred. DotNetNuke.Web.UI.WebControls.TermsSelector with ID='termsSelector' was unable to find an embedded skin with the name 'Simple'. Please, make sure that the skin name is spelled correctly and that you have added a reference to the Telerik.Web.UI.Skins.dll assembly in your project. If you want to use a custom skin, set EnableEmbeddedSkins=false.
I have tried adding the following appSettings to the web.config but not having any luck in fixing the problem or even changing the error message to reflect another skin name.
<add key="Telerik.EnableEmbeddedSkins" value="false" />
<add key="Telerik.ComboBox.Skin" value="Glow" />
<add key="Telerik.Skin" value="Silk"/>
<add key="Telerik.EnableEmbeddedBaseStylesheet" value="false" />