invalid_feed_start_date: GTFS validation rule (feed_info.txt) Error
feed_start_date is not in YYYYMMDD format.
What the rule checks
feed_start_date is not in YYYYMMDD format.
Severity: error
An error marks data that breaks the GTFS specification. A journey planner or a rider app may refuse the file, or show a wrong version of it. Correct it before publishing the GTFS.
Where it applies
The rule applies to feed_info.txt. This file describes the dataset itself: its publisher, language and validity period.
Finding and correcting it
Open the GTFS in GTFS Express. Reading is free, and the validation, by the MobilityData validator and the rules of GTFS Express itself, lists the occurrences of invalid_feed_start_date with the file and rows involved. The correction is made in a draft, by hand or from a brief, with the licence: the corrected GTFS is validated again before it is delivered, and the change can be undone.
In the MobilityData validator
The MobilityData GTFS validator reports this defect as invalid_date, which GTFS Express narrows down to invalid_feed_start_date. Its documentation describes each rule: MobilityData validator rules.