typo3-upgrade-effort-model

TYPO3 Upgrade Effort Model

Generic effort estimation model for TYPO3 LTS major version upgrades. Captures what makes an upgrade hard (per-version breaking-change deltas, Rector coverage, ecosystem readiness); your team's historical data captures how fast you handle each unit.

Calibration is intentionally external. The model gives per-extension hour ranges; you supply the multiplier from your own projects.

When to Use

• TYPO3 upgrade estimation: "v13 → v14.3 LTS effort?"
• Extension compatibility: "Which extensions need updates for v14?"
• Skip-version vs incremental decisions

v14.3 LTS Headline

The largest breaking-change cycle in years — 98 breaking + 31 deprecation entries, all in v14.0. Sprint 14.0–14.2 are unsupported.

Most impactful v14 multipliers (full table in references/risk-multipliers.md):

Factor	Multiplier
TypoScriptFrontendController removal (#107831)	× 1.3
Fluid 5 strict VH typing (#108148)	× 1.2
Core asset concat/compression removal (#108055)	× 1.2
HashService removal, magic finders	× 1.1 each
TCA sweep / EXT:form / ext_tables.php deprecation	× 1.05–1.2

Rector: 47 v14 rules; discount × 0.80–0.85 vs hand-coded. Post-upgrade: +0.5–1 h for #109585 wizard if project transited through v14.2.

Baselines (before calibration)

Path	Own ext (with Rector)	Stale third-party	Project ops
v13 → v14.3	4–8 h	+2–4 h	+0.5–1 h
v12 → v13.4	3–6 h	+2–3 h	+0.5 h
v11 → v12.4	4–7 h	+3–5 h	+1 h
v10 → v11.5	5–8 h	+4–6 h	+1 h

Multiply by team calibration factor (typically 0.6–1.4).

7-Phase Assessment Workflow

1. Discovery — versions, extension inventory, build tooling
2. Classification — see references/extension-classification.md
3. Compatibility matrix — see references/version-compatibility.md
4. Custom code analysis — grep triggers, see references/assessment-workflow.md
5. Risk calculation — compound multipliers from references/risk-multipliers.md
6. Work estimation — extension_hours = baseline × Π(multipliers) × rector_discount × calibration
7. Timeline — phased approach with validation gates

Companion Skills

• typo3-conformance-skill — quality scoring (feeds risk multiplier)
• typo3-testing-skill — coverage assessment
• typo3-extension-upgrade-skill — performs the upgrade
• typo3-project-upgrade-skill — deployed-project upgrade

For Netresearch-internal calibration with historical project data, see coding-ai/typo3-upgrade-estimator-skill (consumes this model).

References

• references/risk-multipliers.md — full per-version table
• references/version-compatibility.md — TYPO3 ↔ PHP matrix
• references/extension-classification.md — categories and risk
• references/assessment-workflow.md — command-level workflow
• references/rector-coverage.md — Rector counts and discounts