You can simply use android:src attribute instead compat attribute when you set vector resource by DataBinding.
DataBinding library generates class that execute setImageResource method at runtime.
<ImageView
...
android:src="https://stackoverflow.com/questions/35766898/@{@drawable/your_drawable}"
/>
According to http://android-developers.blogspot.com/2016/02/android-support-library-232.html setImageResource method can be used at runtime on older system versions without any additional changes.
If you would like to use app:srcCompat attribute. You must define @BindingMethods annotation which connects attribute with appropriate setter from ImageView. For example in your Activity or Fragment add.
@BindingMethods({
@BindingMethod(type = android.widget.ImageView.class,
attribute = "app:srcCompat",
method = "setImageDrawable") })
public class MainActivity extends AppCompatActivity {
// your activity body here
}