vaadin-maven-plug compile widgetSet error

Vaadin 6 / 7 / 8
1

Hi all, i am relatively new to vaadin. i recently migrated from vaadin 7 to vaadin 8. I am trying to compile the widgetSet but i am getting the following error:

[INFO]
 Compiling module com.example.vaadin.widgetset.my_1_4Widgetset
[INFO]
    Found 0 cached/archived units.  Used 0 / 5321 units from cache.
[INFO]
    Compiling...
[INFO]
       20% complete (ETR: 17 seconds)
[INFO]
       20% complete (ETR: 17 seconds)
[INFO]
       20% complete (ETR: 17 seconds)
[INFO]
       30% complete (ETR: 13 seconds)
[INFO]
       40% complete (ETR: 10 seconds)
[INFO]
       50% complete (ETR: 8 seconds)
[INFO]
       60% complete (ETR: 7 seconds)
[INFO]
       70% complete (ETR: 5 seconds)
[INFO]
       80% complete (ETR: 3 seconds)
[INFO]
       90% complete (ETR: 2 seconds)
[INFO]
       100% complete (ETR: 0 seconds)
[INFO]
       Compilation completed in 20.59 seconds
[INFO]
    Tracing compile failure path for type 'com.vaadin.client.ui.notification.NotificationConnector'

[INFO]
       [ERROR]
 Errors in 'jar:file:/Users/user/.m2/repository/com/vaadin/vaadin-client/8.10.2/vaadin-client-8.10.2.jar!/com/vaadin/client/ui/notification/NotificationConnector.java'


[INFO]
          [ERROR]
 Line 36: Type mismatch: cannot convert from Class<Notification> to Class<? extends Connector>
1. [INFO]
       Checked 1 dependencies for errors.