In a direct communication, the source explained:

CBS published revised annual GDP data for the period 2000-2016 on 23 May 2018.

CBS published revised quarterly GDP data for the period 2000-2017 on 1 June 2018.
In the First Release was written:

This First Release presents also the revised time series of data on gross domestic product (GDP) for the quarters from 2000 to 2017. Quarterly data have been revised according to annual data presented in the First Release “Annual Gross Domestic Product, 2000– 2016, Revised Data”.

Data for all quarters for the period from 2000 to 2016 have been adjusted with the annual GDP calculation, while data for all quarters of 2017 are provisional and calculated according to the preliminary quarterly calculation.

Data for the period 2000-2016 are final annual data. Data for 2017 are provisional data.

The series reside in the historical catalog (Croatia » National Accounts » By expenditure | By value add » Quarterly | Annual) and include, for example:

• NALEFCUQ.IHRV     = National accounts: Expenditure approach - Final consumption expenditure - Total, (Mil. HRK, NSA)
• NACSGVATUQ.IHRV = Production approach - Gross value added - Total, (Mil. 2010 HRK, NSA)
• NACEGFCFUA.IHRV = Expenditure approach - Gross capital formation - Gross fixed capital formation, (Mil. 2010 HRK)

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.