Skins errors after upgrading to version DNN10

[FastInvestments]

Hello. Can you help me figure out what needs to be removed or replaced to restore functionality?
Or is it impossible for a beginner to cope with this and need to look for a new skin for the site?

Unable to load template: /Portals/_default/skins/car dealer-read/article_1.ascx, Error: Failed to load type 'DotNetNuke.UI.Skins.Controls.LeftMenu'.

[Timo-Breumelhof]

The Skin uses one of the deprecated Theme object (leftmenu) which has been removed in DNN 10.
(I guess this a quite an old Theme / Skin..)
If you have access to the ascx files of the Theme, you can remove the reference to Leftmenu.
You would probably want to replace it with the newer DDR menu.

You can find example of DDR here: https://github.com/40fingers/DNN-DDR-Menu-Theme-Demo
Documentation: https://docs.dnncommunity.org/content/tutorials/themes/theme-objects/ddrmenu/index.html

[FastInvestments]

Thank you for your reply! It turned out to be just a vestige that needs to be removed.