While we were trying to migrate the User profile DB along with the Mysite from SharePoint 2010 to SharePoint 2016 by having a hop at SharePoint 2013 , we faced the below issue
It worked all fine in SharePoint 2013 , but had some issue in SharePoint 2016
Web Part Error: A Web Part or Web Form Control on this Page cannot be displayed or imported. The type could not be found or it is not registered as safe
On closer look at the web.config and logs , I found that the entries were missing for 14.0.0.0 version in Sharepoint 2016 , fix was to add below entries in web.config file which was hosting the Mysite webapplication
<SafeControl Assembly="Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" Namespace="Microsoft.SharePoint.WebPartPages" TypeName="BlogAdminWebPart" Safe="True" SafeAgainstScript="True" />
<SafeControl Assembly="Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" Namespace="Microsoft.SharePoint.WebPartPages" TypeName="BlogLinksWebPart" Safe="True" SafeAgainstScript="True" />
<SafeControl Assembly="Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" Namespace="Microsoft.SharePoint.WebPartPages" TypeName="BlogMonthQuickLaunch" Safe="True" SafeAgainstScript="True" />
<SafeControl Assembly="Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" Namespace="Microsoft.SharePoint.WebPartPages" TypeName="BlogYearArchive" Safe="True" SafeAgainstScript="True" />