Basically, the migration module does not support migrating custom controls/modules that were used in 3.7 to 4.x / 5.x/ 6.x as the differences in the architecture and structure ( and logic ) between the 3.x versions and the 4.x / 5.x/ 6.x is huge and can hardly be covered by the migration service. Therefore all controls that you have created in 3.x ( that do not come out of the box in Sitefinity 4.x / 5.x/ 6.x ) need to be rewritten using our 4/5/6.x API. You cal also use Sitefinity thunder add - on for creating widgets and modules easily.
We also have a KB article on how to migrate custom widgets to 4.x / 5.x/ 6.x:
The best option in your case would be, knowing the 3.x implementation and the final result of each control to redesign and recreate the controls in a way that you can achieve the same result in Sitefinity 4.x/ 5.x/ 6.x In order to replicate the behavior of controls for the new Sitefinity website, I would suggest to review the following resources:
1. Developer documentation.
2. How to ( custom code samples )
3. Our SDK
4. Our Blogs
, which contain posts with custom implementations.
5. API reference.
We have API reference, which can help you through the development process - if you want to get the latest release of the API reference document, you can check the following article, which contains a direct link for downloading the files:
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items