The source wrote (citation):

We would like to inform our kind users that the territorial code system was modified on 1 January 2018 (Decree No. 39/2017. (XII. 27.) of the Minister of Prime Minister’s Office, amending Decree No. 31/2011 (X. 24.) of the Minister of Public Administration and Justice on the territorial registration identification code system entered into force). The modification was justified by international and national legislative changes, in accordance with which several territorial classifications have been modified. In view of user needs, new nomenclatures have also been incorporated into the territorial code system. Based on the changes, Budapest and Pest county are also planning and statistical regions, while Central Hungary became exclusively a statistical large region.

That is:

• The region of NUTS 1 "Central Hungary" has been fissioned to two NUTS 2 areas, "Budapest" and "Pest".

In response, we have:

1. Marked as discontinued the 20 series with the predecessor geo:

• IHUN_KM = Central Hungary

2. Added 43 series for the successor geos:

• IHUN_PE = Pest (27)
• IHUN_BU = Budapest (16)

3. Renamed six series for Budapest (old » new):

• IHUN_BUD » IHUN_BU

The series reside in the historical catalog:

• Hungary » Real Estate » Residential » Prices » Areal price
• Hungary » Real Estate » Residential » Prices » Mean price
• Hungary » Real Estate » Residential » Sales » Annual

References

• Classification - TSZJ

See also

• Mnemonic change: Hungary subnational - Res sales (Nov 2019)