White notification icon - Android 5.0 Lollipop

 //add this line to your android manifest file : i have tested this !!
   <!-- GCM requires Android SDK version 2.2 (API level 8) or above. -->
     <uses-sdk
         android:minSdkVersion="8"
         android:targetSdkVersion="16" /> 

We're using a plugin called ELAN. It lets you use an icon different from the app icon which will be used for the notification.

Here's the plugin: https://www.assetstore.unity3d.com/#!/content/9484

The trick is to use this to generate your notification icon: http://romannurik.github.io/AndroidAssetStudio/icons-notification.html

The drawable folders should be inside this folder: (Assets/Plugins/Android/res/)

Basically you need to setSmallIcon of notification builder to the required bitmap.

Just to let you know, We recently released Cross Platform Native Plugins

This handles coloured and white icons according to the target platform.

If you can let me know which plugin you are using probably I can guide you better.

I haven't tested it myself but I heard if you set the targetSdk < lollipop then it'll work:

   <uses-sdk android:minSdkVersion="9" android:targetSdkVersion="19" />
 

Hi @Klvana,

• What if we want to use white notification icon for SdkVersion > 20 and another colored notification icon for SdkVersion <= 20?

This is gracefully solved in our plugin UTNotifications. It provides you two options: enabling Android 4.4 Compatibility Mode (which sets targetSdkVersion to 19) or set separate notification icons for Android 5.0+ and lesser versions of Android. It also contains solutions for other Android (and not only) related issues, f.e. restores scheduled notifications after a device reboot, which is not supported by Android directly.