The draft scheme requires the use of SSR transponders in mode S/ELS for flights performed under visual flight rules outside the uniform daylight period (between sunset and sunrise)

Arrangement of the Minister for Infrastructure and Water Management, of...., No IENM/BSK-2021/....., amending the Exemption scheme by Air Traffic Decree 2014 related to the introduction of the obligation to use a transponder in operations outside the daylight period

The draft scheme requires the use of an SSR transponder in mode S/ELS for the performance of a flight under visual flight regulations in the dark.

The purpose of this is that the red obstacle lighting on windmills by detection of the SSR transponder on the aircraft only needs to be lit when there is an aircraft near the windmill, and light pollution and light pollution for residents are reduced to such extend.
This means that aircraft that do not yet have an SSR transponder must be equipped to fly in the dark.
The obligation is set out in Article I, part B, of the draft scheme.
The obligation does not therefore impose technical requirements on the transponder itself, but only requires its use.
There is no provision on mutual recognition because the intended purpose cannot be achieved in any other way than through the use of the SSR transponder.