EXPIRED LITECOIN INVOICE: TEACHING CASEBOOK
Version 2026-10-12-v1. Source review 12 October 2026.
Responsible author/editor: Jarosław Wasiński.

Original contribution
The ten cases connect a buyer's retry decision with a declared deadline, exact
amount, network and destination evidence, observation type and supplied service
snapshot. A wallet's send time, receiver first observation, confirmation
observation, header timestamp and provider credit are recorded separately.
The equality boundary is deliberately undecided. BitPay is a separately cited
policy example; the casebook is not a simulation of BitPay behavior.

Fixtures and reproducibility
All values, timestamps, statuses and labels in invoice-cases are fictional.
No mainnet transaction, wallet/camera test, support ticket, merchant deployment
or measured response time occurred. No live account or usable address/TXID is
present. CSV empty cells and JSON null mean UNKNOWN, not zero or failure.
The service status is supplied evidence, never computed from time/amount alone.
The decision output identifies a next question, not acceptance or recovery.

To verify independently with Python 3 standard library only:
1. Download invoice-cases.json, invoice-cases.csv, fictional-valuations.json,
   fictional-valuations.csv and reproduce.py.txt to one local folder.
2. Rename reproduce.py.txt to reproduce.py if preferred, or run it directly:
   python reproduce.py.txt
3. Read its 10-case comparisons and arithmetic results. No network connection,
   provider API, external dependency or payment is used. It creates no files.
It checks expected labels independently from the separately supplied inputs.
It rejects timezone-free timestamps and uses integer litoshis/Decimal values.
An additional check shows that changing block header time does not change a
receiver-observation comparison, and preserves the unclassified exact boundary.

Declared model
Deadline 2026-10-12T12:15:00+02:00 = 2026-10-12T10:15:00Z.
An explicit offset describes this instant; it does not establish a recurring
timezone or daylight-saving rule. before/at/after label temporal relation only.
Original quote EUR 24 at EUR 60/LTC gives 40,000,000 litoshis.
Hypothetical new quotes EUR 48/60/80 per LTC require 50,000,000/40,000,000/
30,000,000 litoshis for a fresh EUR 24 quote. Their difference is not a top-up
instruction or refund entitlement. Fees/spreads excluded in the valuation table.

Scope and source policy
Ordinary transparent native Litecoin. No private MWEB reconstruction, unsupported
network recovery promise, custom timed-script claim or guaranteed fulfillment.
BitPay consumer help describes 15 minutes and a declined late-payment/refund
workflow; API acceptanceWindow is configurable, so read the actual invoice.
The refund-claim link deadline is separate. The cited BTC confirmation examples
conflict across docs and are not used to supply any Litecoin threshold/timing.
Source URLs/review dates and prior-article differentiation are in sources.json.
An explorer outage is not cancellation and an input address is not a verified
refund destination. The authenticated receiver determines its commercial policy.

Publication
Intended public folder /uploads/research/invoice-expiry-20261012-v1/.
Download files: invoice-cases CSV/JSON, fictional-valuations CSV/JSON, checklist,
private-support-template, reproduce.py.txt, sources.json, README, validation.json,
and SHA256SUMS.txt. The accompanying article and illustrations are published separately.
Keep completed worksheets/support records private. No recovery secret is needed.
Research and drafting used AI assistance. No independent external review claimed.