> ## Documentation Index
> Fetch the complete documentation index at: https://docs.graphora.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Neo4j Compatibility

> Tested Python, driver, server, and Cypher combinations and the support policy

GraphCheck keeps the Python driver, Neo4j Server, and Cypher language versions separate. The
tested release matrix for GraphCheck 0.2 is:

| Dimension           | Tested target                      | Policy                           |
| ------------------- | ---------------------------------- | -------------------------------- |
| Python              | 3.12 and 3.13                      | Both run the unit gate           |
| Neo4j Python driver | 5.20.0                             | Minimum supported driver         |
| Neo4j Python driver | latest 6.x                         | Primary driver line              |
| Neo4j Python driver | 7.x                                | Excluded until tested            |
| Neo4j Server        | 5.26.28 Community and Enterprise   | Neo4j 5 LTS target               |
| Neo4j Server        | 2026.06.0 Community and Enterprise | Selected calendar-version target |
| Cypher              | 5                                  | Tested on 5.26.28 and 2026.06.0  |
| Cypher              | 25                                 | Tested on 2026.06.0              |

The production dependency is bounded to `neo4j>=5.20,<7`. CI installs 5.20.0 and the latest
available 6.x release independently, so a future untested driver major cannot enter dependency
resolution. The driver APIs used at the compatibility floor are `GraphDatabase.driver`,
read-access sessions, explicit transactions, `neo4j.Query` timeouts, result summaries and plans,
query-type classification, notifications, and GQL status objects with compatibility fallbacks.

Server images are exact rather than floating: `neo4j:5.26.28` and `neo4j:2026.06.0`, with matching
`-enterprise` images for the built-in `reader` role gate, effective privileges, HOME database, and
restricted-credential checks. The current server runs separate database-default Cypher 5 and
Cypher 25 lanes. See Neo4j's
[server archive](https://neo4j.com/docs/reference/docs-archive/),
[driver API](https://neo4j.com/docs/api/python-driver/current/), and
[Cypher version configuration](https://neo4j.com/docs/operations-manual/current/configuration/cypher-version-configuration/).

## Neo4j 4.4 policy

Neo4j 4.4 is legacy and unsupported by GraphCheck 0.2. It is absent from CI, and the connector
returns `neo4j.unsupported_version` during the target probe with a 5.26 LTS upgrade direction.
GraphCheck evidence identity now uses `elementId()`, avoiding the deprecated numeric `id()` API.

## Cypher 25 and sampling

Evidence identity, deterministic evidence ordering, uniqueness comparison, drift evidence, and
profile type sampling use opaque `elementId()` strings without parsing their format.

Hub and PII bottom-k sampling deliberately retain numeric `id()` only inside queries explicitly
prefixed with `CYPHER 5`. Their established seeded cubic hash requires a numeric input, while Neo4j
does not guarantee a parseable `elementId()` format. This explicit compatibility path works on a
Cypher 25-default database without silently changing sample selection. A future string-hash
sampling algorithm must be versioned and distribution-tested before those two `CYPHER 5` prefixes
can be removed.

## Support output

`graphcheck debug` reports four distinct values: GraphCheck version, Neo4j Python driver version,
Neo4j Server version, and the configured database's Cypher version. `debug --json` exposes the same
values under `versions`. On calendar-version servers, Cypher mode detection is best effort for
restricted credentials; if database metadata is hidden, it reports `unknown` rather than claiming
Cypher 5 or 25.

## Installed-wheel gate

CI builds the wheel, installs it into a clean environment, runs `graphcheck --version` and
`graphcheck --help`, and verifies the installed core and PII pack resources. This catches source
tree assumptions that the regular development environment would hide.