On 22 June in its StatLine data portal, the source wrote (citation):

Tabeltoelichting
[...]
Wijzigingen per 6 juli 2018:
De cijfers zijn geactualiseerd. De cijfers over de vorige perioden kunnen zijn bijgesteld.

That is:

Table explanation
[...]
Changes as of 6 July 2018:
The figures have been updated. The figures for the previous periods may have been adjusted.

In response, we have:

1. Archived the predecessors (as early as 1999Q1 to 2017Q4) by renaming with an "_17" specifier, by marking metadata as "discontinued," and by segregating in the catalog.
2. Created one-for-one replacements. Properties are otherwise unchanged (see related article).

The active series reside in the historical catalog (Netherlands » Government » Government Finance » Quarterly, from 1999) and the predecessors under the associated "discontinued" node (Quarterly, 1999 to 2017). They include, for example:

• GVLGBGB_17UQ.INLD  = [DISCONTINUED] Government finance: General government - Balance, (Mil. EUR, NSA)
• GVLGBGBUQ.INLD     = Government finance: General government - Balance, (Mil. EUR, NSA)
• GV%GDCG%GDPUQ.INLD = Share debt as a share of GDP, (%, NSA)

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

• New Data: Netherlands - EMU finances of government - Addendum(Apr 2015)
• Data Change: Netherlands - GDP - Redefined and re-referenced
• Data Change: Netherlands - Sector account for households - Redefined