Hi Andreas,
Thank you for using Syncfusion Products.
We have checked with the reported query “NullReferenceException thrown after updating Xamarin.Forms version to 2.4.0.18342” from our side and referred the attached stack trace. Unfortunately the reported issue does not reproduce at our end. But based on the stack trace, we suspect that the error may have occurred due to unsupported Color in latest version of Xamarin.Forms which is bound to Label’s TextColor property. So we highly recommend you to use Hexadecimal values of color codes to avoid the confusion. For your reference, we have attached our sample link below.
Please let us know if you require further assistance.
Regards,
G.Muthu Kumaran.