Upgrading from 2.4 to 2.5
See Release notes of DotVVM 2.5 Preview 2 and Release notes of DotVVM 2.5 for complete list of changes.
Breaking changes
REST API bindings upgraded to latest Swashbuckle.AspNetCore
The DotVVM.Api.Swashbuckle.AspNetCore package now references Swashbuckle.AspNetCore 5.4.1 which works with both ASP.NET Core 2.x and 3.x. If the API consumed by DotVVM app is hosted in ASP.NET Core 2.x, or if it explicitly uses the Newtonsoft.Json serializer in 3.x, you'll need to install Swashbuckle.AspNetCore.NewtonsoftJson package as well, otherwise the Swagger metadata won't be produced correctly.
DotVVM doesn't rely on DefaultSettings
If you made some changes in Newtonsoft.Json's DefaultSettings serializer configuration object, these changes were used by DotVVM until DotVVM 2.5. From this version, we are using our own instance of JsonSerializerSettings, so these changes are not applied to DotVVM serialization any more.
If you registered your own converters so you could transfer your own objects in the viewmodel, and then used JavaScript to work with such objects, this code will probably break.