Migrate to 9.0.0
These are the changes made for 9.0.0 that are breaking or just important to know
This Guide is written for migration from version 8.3.0 to 9.0.0, for versions >9.0.0 <10.0.0, please consult the CHANGELOG
Requirements changed
- Mongoose 
6.0.7or higher is now required - Typescript 
4.4is now suggested to be used 
Mongoose 6.0 is now supported
Mongoose version 6.0.7 (and possibly higher) is now supported, for mongoose specific migration, look at the 6.0 migration guide
Class-transformer transform of "ObjectId" became broken
Since mongodb 5.0 (mongoose 6.0) the value in @Transform is not equals to obj[key] anymore, see the updated Class-Transformer Guide and the Issue about this
Build order for Class-to-Schema changed
The build order for Class-to-Schema (buildSchema) changed from "top-down" to "bottom-up"
Error "E007" got removed
The Error E007 got removed, because get and set options can be defined independently of eachother.
Error "E023" got merged into "E013"
The Error E023 got merged into E013.
Errors "E008" & "E015" & "E022" got merged into "E026"
The Errors E008 & E015 & E022 got merged into a new Error, E026.