I’m not sure to recognize the right pattern, and I’m not sure how this file is used at all. 
As you’re making a big jump from v2 to v7, the simplest would be to refer to the archive I shared here. It contains the source code of a project I just created with forest-express-mongoose.
You can refer to it to see how your code should be migrated, and the overall changes that have to be made.
The objectives, at the end, is that:
- Your argent should be running, without error
- Calling
GET /forestshould return a 204 (empty response) - Calling
POST /forest/authenticationshould return a valid response