Kernrechtsfrage
Whether the cantonal court correctly held the appeal time-barred
Extrahierter Entscheid
The postal receipt makes timely filing plausible; the existing file does not conclusively resolve when the appeal was handed to the post.
Extrahierte Begründung
The Federal Court accepted the receipt as a permissible new piece of evidence and noted that the file only showed later sorting and stamping, not the actual handover time. Further clarification is needed.