Free VS Pro in Android, worth Upgrading?

Question

Hi everyone,

I came across Zoiper IAX SIP VOIP Softphone (https://play.google.com/store/apps/details?id=com.zoiper.android.app) and Zoiper Pro (https://play.google.com/store/apps/details?id=com.zoiperpremium.android.app) on Android. The Pro version mentions several updates, but they seem minor. Could someone clarify the complete differences between the two versions? Is it worth paying for Zoiper Pro?

Major changes in Zoiper Pro:
- new gui
- multiple and custom color themes
- better bluetooth support
- reworked network change
- new notification system

Thanks!