Is there anything special that I need to do to replace the old SDK with the new/GA one?

Yes, you will need to install CE 3.0 SDK and for an existing snap-in make update to SDK reference. Please follow these steps:

1) Delete exiting local Maven repository to clear old SDK files.
For Windows 7/8, delete files located under directory C:\Users\<your-username>\.m2\
For Linux, delete files located under ~/.m2

2) Download CE 3.0 SDK from DevConnect Portal. Please see http://www.devconnectprogram.com/site/global/products_resources/avaya_aura_collaboration_environment/releases/3_0/index.gsp
Select Downloads --> CE API Resources --> Select link to download SDK (Avaya Aura Collaboration Environment SDK)

3) Extract the CE 3.0 SDK zip file and execute install script (install.bat or install.sh based on your OS) to install CE 3.0 SDK

4) Now the CE 3.0 SDK is installed. If you have an older version of snap-in (e.g. compiled for CE 2.0), you will need to make some updates in pom.xml. Please see Avaya Aura® Collaboration Environment Service Development Guide from link provided in step 2 above. See Chapter 2 - section Converting CE 2.x project to project 3.0. For new snap-in, follow directions within the same guide in Chapter 1 - Creating a Service Project

Thanks!