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Depends if you care about names or about physics. Radio, Infrared Gamma etc are just names we give to various parts of the continuous electromagnetic spectrum. The edges of these definitions are not super well defined. Changing from RF to microwave could be defined at say about 3 GHz, but there is not some clear physical difference between a 2.9 GHz photon and a 3.1 GHz photon other than the frequency change.
The lower limit to the frequency is I guess the inverse of the theoretical age of the universe/2. Something can't currently be oscillating slower than that.
There are some theories on plank length, quantisation limits, etc that might set some theoretical upper limit of photon frequency. But we don't appear to be anywhere close to observing such things. We have seen some rather crazy short wavelength particles that we haven't fully understood.
Upvoted just because scientists have some wonderfully whimsical names for their discoveries.