How to upgrade the DHTMLX ?

Hi Team,

We are using the DHTMLX in my application. Recently we got the upgrade link path from the supporting team. As of now, we have start to update the code. Can u please advise me.
How can i start my work?
How many hours to take time to convert it? Mostly we are using the DHTMLX Grid ,Combobox and some component.

Please help me,

Please, refer to the following migration guide: