It was rolled out to Early Access Program members in mid-April, but now everyone is getting it.

If you have a Tesla with the latest hardware 3 with the fully-featured Autopilot, then your car will gain traffic light and stop sign recognition as of the Software Update 2020.12.6. However, it will apparently only be available to Tesla owners in the US and other markets will have to wait a few more months to get this feature, although owners in the UK seem to have already received it (as per the video above).