The source explains (citation):

The Central Statistics Office (CSO) has today (21 September 2016) launched a new Residential Property Price Index (RPPI) for Ireland which covers all market transactions in the residential property market and measures price change with greater accuracy.

The new RPPI represents a significant methodological improvement over the original RPPI as it includes cash purchases of property, higher quality data sources* and more detailed locational characteristics of dwellings.

It includes twelve new sub-indices. Seven of these relate to regional price indices (Border, Midland, West, Mid-East, Mid-West, South-East, South-West), four relate to Dublin price indices (Dublin City, Dun Laoghaire-Rathdown, Fingal, South Dublin) and one is a price index for apartments outside of Dublin.

1. In response, we have archived the predecessors (January 2005 to June 2016) by marking their metadata as "discontinued" and by segregating in the catalog. For the replacements, properties are unchanged.

The series reside in the historical catalog (Ireland » Real estate » Residential » Prices » Residential Property Price Index (RPPI)) and include, for example:

• HPIRESUM.IIRL        = [DISCONTINUED] House Price Index: All Residential Properties, (Jan2005=100, NSA) - for Ireland
• HPITRESUM.IIRL       = Residential property price index - New and existing - All residential properties, (Index Jan2005=100, NSA) - for Ireland
• HPITAPTUM.IIRL_DBL   = New and existing - Apartments - for Dublin

Because catalog locations are subject to change, the upper-right search box on DataBuffet.com provides a "find in catalog" mode that accepts a mnemonic.

2. The new series start at January 2010, but properties are otherwise the same. They include, for example:

• HPITHOUUM.IIRL_2103 = New and existing - Houses - for Fingal
• HPITAPTUM.IIRL_XDBL = New and existing - Apartments - for Ireland excl. Dublin

3. Please note that we have created a new geo code for "Ireland outside Dublin" so you can now retrieve all geographically related series with a single concept code. For example:

• HPIRESXUM.IIRL      = [DISCONTINUED] All residential properties excl. Dublin - for Ireland
• HPITRESUM.IIRL_XDBL = All residential properties - for Ireland excl. Dublin
• HPITRESUM.IIRL?     = All residential properties - for all three geos