I am using libGoogleAnalyticsServices.a library in my client app for Google Analytics 360. As per below URL, google analytics sdk are going to get the sunset.
https://support.google.com/firebase/answer/9167112?hl=en
In the above URL, It mentioned that "Google Analytics 360 customers’ properties are not affected.". What does it mean?
As a 360 customer, should I need to migrate to firebase or not?
It means that you don't need to do anything if you're a GA360 customer and the property used for the GA Mobile SDK is a 360 property.
In terms of migration or not, that's really an internal discussion within your team. Many factors affect this. Sure the sunset might be a hint for what's to come, but we have no idea of timelines for 360 customers. IMO you should maybe do a discovery with Firebase, since the way it tracks data is a different way of thinking than the GA mobile SDK. Then you would have a better idea of what's required to migrate and when you can fit it in.