The source wrote (citation):

NUT2 and NUTS3 regions
[...]
Revisions were made to the NUTS boundaries in 2016 and were given legal status under Commission Regulation (EU) 2016/2066 amending annexes to NUTS Regulation 1059/2003. Under this revision the NUTS 2 Regions comprise the Regional Assemblies established under the Local Government Act 1991 (Regional Assemblies) (Establishment) Order 2014 (SI No. 573 of 2014). The NUTS 3 Regions are groupings of 31 administrative counties, and nest into the NUTS 2 Regions.

In response, we have:

1. Archived 704 predecessors (16 concepts and 44 geos, table BHQ02, NUTS 2013, 2001Q1 to 2017Q4) by renaming with an "_G13" specifier and by marking metadata as "discontinued".
2. Created 668 replacements (16 concepts and 42 geos, table BHQ12, NUTS 2016) which start at 2018Q1.
3. No change for tables BHQ03 or BHQ05.
4. Where possible, for composite areas that are reported from 2018Q1, we have extended back to 2001Q1 by aggregating their components.
5. Replaced four calculated series (2 concepts, 2 geos). The new geos are IIRL_13GA and IIRL_25CO.
6. Discontinued 92 SA supplements (2 concepts, 46 geos).

Dataset properties:

• Measurement: Unitary count (#) or square meters (sqm)
• Adjustment: Not seasonally adjusted (NSA)
• Geo coverage (before » after)
• IIRL_aa   = NUTS level 2, 2 » 5
• IIRL_aaa  = NUTS level 3, 8 » 12
• IIRL_aaaa = CSO province, 0 » 0
• IIRL_nnaa = CSO aggregate of administrative counties, 4 » 4
• IIRL_nnnn = CSO administrative county, 32 » 37
• Do all concept-geo combinations exist: No
• Native frequency: Quarterly
• Start date:
• As reported: 2018Q1
• Extended: 2001Q1

The concepts reside in the historical catalog:

• Ireland » Real estate » Residential » Stage of construction » Permits » Not seasonally adjusted » Type of dwelling

and include, for example:

• HSQAPMT_G13UQ.IIRL_2503 = [DISCONTINUED] Permits for private flats/apartments, (#, NSA) - for [CSO province] Kerry, 2001Q1 to 2017Q4
• HSQAPMTUQ.IIRL_2503     = Permits for private flats/apartments, (#, NSA) - for [CSO province] Kerry, from 2018Q1
• HSQHPMT_G13UQ.IIRL_SOW  = [DISCONTINUED] Permissions for houses, (#, NSA) - for NUTS (2013) 3 South-West, 2001Q1 to 2017Q4
• HSQHPMTUQ.IIRL_SOW      = Permits for houses, (#, NSA) - for NUTS (2016) 3 South-West, from 2018Q1

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.

See also

• Geography Change: Ireland subnational - NUTS 2016