Kernrechtsfrage
Whether the appeal had to be declared inadmissible because the advance of costs was not paid within the supplementary deadline.
Extrahierter Entscheid
Yes. Since the required advance was not paid within the non-extendable supplementary deadline, the appeal had to be declared inadmissible under Art. 62(3) LTF.
Extrahierte Begründung
The court held that a supplementary deadline for an advance of costs is generally non-extendable and may be extended again only exceptionally upon concrete, unforeseeable reasons, which were not shown here.