It is unusually warm in Tokyo Japan where I live. Summer flowers are still fully blooming, and cluster amaryllis which should be blooming by autumn equinox delayed by one week.
However, it will be good that curry leaf growers like you are to start preparing overwinter now. We shall not forget that the curry leaf plant slows down its growth when average temperature goes below 18-20 deg C (65-70 deg F). Color of the leaves gets faded and starts loosing the leaves when the temperature gets lower.
It means that overwintering method depends on if an ambient temperature around the plant can be kept at 18 deg C or not.
There are two ways to overwinter.
Bring the plant inside and keep it until spring.
Leave the plant outside where the soil do not get frozen, or sunny enough. Planting to the ground is also possible depending on the area and how sunny the spot is.
Bring the plant inside
Takes up some space in the room.
Need to water time to time.
Spider mites could proliferate due to dry ambient from room heating
No natural enemies for the harmful insects such as aphid
May not initiate flower buds by cold ambient
Curry leaves within a reach at anytime (leaves may fall off if the room temperature is relatively low)
Leave the plant outside
Will not have leaves for use until next spring, once the leaves fall off.
Might damage the roots by over watering
Might dry up the plant if you forget to take care
Higher probability to initiate flower buds which should result in delivering fruit.
There are pros and cons on both ways, however, I would keep one inside for use at anytime, and leave on outside if I had two plants or more.