If you are going to conduct any business in Georgia, it is recommended to file with the State as a foreign corporation with a registered agent identified, and keep your registration current.
***This Reply does not constitute legal advice and does not create any attorney-client relationship. The Asker of the Question is urged to consult legal counsel.
You will have people working there, you will presumably be renting office space there, having workers comp coverage there and all of the other similar things that go along with operating a business, even if there is no sales complete there. It does give you additional rights there, such as being entitled to file a lawsuit in the State's courts if need be.
It is risky not to continue your registration there. I am not a Georgia attorney, so this really is more of a suggestion than any legal advice, but here in Ohio for what you are saying you will be doing, the cost of continued registration is so small that it would be foolish not to continue it.
As others have said, if you have an office and employees in Georgia, you are "doing business" in Georgia. You should maintain your Georgia registration.
[This communication is intended as general information and not specific legal advice, and this communication does not create an attorney-client relationship.]
If you are leaving a team of employees in Georgia, you will likely generate enough qualifying activity to be deemed "doing business in Georgia". Additionally, business registration affords you certain rights and/or protections that you may need to take advantage of in the future. As such, you should probably maintain your registration in Georgia as a foreign company.