Does the 4+4 alternation persist in recent solar cycles?

The solar hemispheres exhibit asymmetries in both timing and intensity of their activity. Investigations of these asymmetries have revealed a long-term hemispheric phase lag. Specifically, a 4+4 Schwabe-cycle variation has been identified: during four consecutive solar cycles the northern hemisphere leads in time, while during the subsequent four Schwabe cycles the southern hemisphere takes over the leading role. This alternating pattern has been observed up to Solar Cycle 23. Whether it also persists in the most recent cycles remains an open question.
This phenomenon has previously been studied using several sunspot databases, including the Greenwich Photoheliographic Result, the Debrecen Photoheliographic Data, and several historical sunspot observations by Schwabe, Staudacher, and Spörer. In the present study Solar Cycles 24 and 25 are investigated using the Solnechnie Dannie and SOON databases. Therefore, hemispheric solar asymmetry can be examined over a period spanning nearly 250 years.
Unlike most previous studies, we characterize hemispheric solar cycles by their centers of mass and calculate the temporal and intensity differences between the northern and southern hemispheric centers of mass.
Our results indicate that Solar Cycles 24 and 25 appear to conform to the 4+4 alternation rule. Since similar periodic behavior has been identified in other solar phenomena, this variation may represent a long-term property of the solar dynamo and may be related to the physical background of the Gleissberg cycle.