[BUG]: VectorCypherRetriever uses deprecated db.index.vector.queryNodes on Aura 5.27 even though SEARCH works

Before You Report a Bug, Please Confirm You Have Done The Following...

• I have updated to the latest version of the packages.
• I have searched for both existing issues and closed issues and found none that matched my issue.

neo4j-graphrag-python's version

1.18.0

Python version

3.13.12

Operating System

Windows

Dependencies

annotated-types==0.8.0
anyio==4.14.2
certifi==2026.7.22
charset-normalizer==3.4.9
colorama==0.4.6
distro==1.9.0
fsspec==2026.7.0
h11==0.16.0
httpcore==1.0.9
httpcore2==2.10.0
httpx==0.28.1
httpx2==2.10.0
idna==3.18
jiter==0.16.0
json_repair==0.63.0
jsonpatch==1.33
jsonpointer==3.1.1
langchain==1.3.15
langchain-core==1.5.4
langchain-openai==1.4.3
langchain-protocol==0.0.18
langgraph==1.2.11
langgraph-checkpoint==4.2.0
langgraph-prebuilt==1.1.0
langgraph-sdk==0.4.2
langsmith==0.10.18
markdown-it-py==4.2.0
mdurl==0.1.2
neo4j==6.2.0
neo4j-graphrag==1.18.0
numpy==2.5.2
openai==2.54.0
orjson==3.11.9
ormsgpack==1.12.2
packaging==26.3
pydantic==2.13.4
pydantic_core==2.46.4
Pygments==2.20.0
pypdf==6.15.0
python-dotenv==1.2.2
pytz==2026.3.post1
PyYAML==6.0.3
regex==2026.7.19
requests==2.34.2
requests-toolbelt==1.0.0
rich==15.0.0
scipy==1.18.0
sniffio==1.3.1
tenacity==9.1.4
tiktoken==0.13.0
tqdm==4.70.0
truststore==0.10.4
types-PyYAML==6.0.12.20260724
typing-inspection==0.4.3
typing_extensions==4.16.0
urllib3==2.7.0
uuid_utils==0.17.0
websockets==15.0.1
xxhash==3.8.1
zstandard==0.25.0

Reproducible example

// Create graph

DROP INDEX chunkEmbedding IF EXISTS;
MATCH (c:Chunk) DETACH DELETE c;

CREATE (c:Chunk {
text: "minimal repro chunk",
embedding: [0.1, 0.2, 0.3]
});

CALL db.index.vector.createNodeIndex(
"chunkEmbedding",
"Chunk",
"embedding",
3,
"cosine"
);

# Python code
import os
from dotenv import load_dotenv
from neo4j import GraphDatabase
from neo4j_graphrag.retrievers import VectorCypherRetriever

load_dotenv()

driver = GraphDatabase.driver(
    os.getenv("NEO4J_URI"),
    auth=(os.getenv("NEO4J_USERNAME"), os.getenv("NEO4J_PASSWORD")),
)

retriever = VectorCypherRetriever(
    driver=driver,
    index_name="chunkEmbedding",
    retrieval_query="RETURN node.text AS text, score",
    neo4j_database=os.getenv("NEO4J_DATABASE"),
)

result = retriever.search(
    query_vector=[0.1, 0.2, 0.3],
    top_k=1,
)

Relevant Log Output

Runtime warning from server:

Received notification from DBMS server: warn: feature deprecated with replacement.
db.index.vector.queryNodes is deprecated. It is replaced by SEARCH.

Generated query starts with:

CALL db.index.vector.queryNodes($vector_index_name, $top_k * $effective_search_ratio, $query_vector)

Expected Result

When SEARCH is available on the connected database, VectorCypherRetriever should use SEARCH instead of db.index.vector.queryNodes, or at least avoid triggering a deprecation warning on normal retrieval paths.

What happened instead?

The retriever uses db.index.vector.queryNodes and Aura returns a deprecation warning on each retrieval query.

Additional Info

Connected DB reports:

• Neo4j Kernel
• 5.27-aura
• enterprise

This suggests the fallback/version gating used by the retriever may be too strict for Aura 5.27, or not aligned with actual SEARCH availability on Aura.

Start with VectorCypherRetriever.search and reproduce the query against Aura 5.27 using the example in the issue. Inspect the version gating or fallback that generates db.index.vector.queryNodes; done means normal retrieval uses SEARCH when available and no longer emits the deprecation warning.