clarification

Author: JPryce-Aklundh

modules/ROOT/pages/deprecations-additions-removals-compatibility.adoc

@@ -157,22 +157,6 @@ dbms.upgradeStatus()
 a| These procedures have been removed from Cypher 25.
 For more information, see the link:{neo4j-docs-base-uri}/operations-manual/current/procedures/[Operations Manual -> Procedures].
 
-a|
-label:functionality[]
-label:removed[]
-[source, cypher, role="noheader"]
-----
-WITH 1 AS g
-RETURN COLLECT {
-        UNWIND [1,2,3] AS x
-        WITH * WHERE x < 0
-        WITH COUNT(*) AS agg
-        RETURN agg + g
-} AS x
-----
-
-a| The xref:subqueries/collect.adoc[`COLLECT`], xref:subqueries/count.adoc[`COUNT`], and xref:subqueries/existential.adoc[`EXISTS`] subquery expressions no longer use imported variables as grouping variables in aggregations.
-
 |===
 
 === Deprecated in Cypher 25
@@ -202,6 +186,35 @@ For more information, see link:{neo4j-docs-base-uri}/operations-manual/current/d
 | Feature
 | Details
 
+a|
+label:functionality[]
+label:updated[]
+[source, cypher, role="noheader"]
+----
+WITH 1 AS g
+RETURN COLLECT {
+        UNWIND [1,2,3] AS x
+        WITH * WHERE x < 0
+        WITH count(*) AS agg
+        RETURN agg + g
+} AS x
+----
+
+a| Imported variables are now correctly handled as constants inside xref:subqueries/collect.adoc[`COLLECT`], xref:subqueries/count.adoc[`COUNT`], and xref:subqueries/existential.adoc[`EXISTS`] subqueries expressions.
+The example query previously returned no results (`[]`) because the imported variable was used incorrectly as an implicit grouping key.
+It now returns `[1]`, since the variable is not used as a grouping key, allowing `count(*)` to return `0` and `0 + g` to evaluate to `1`.
+
+a|
+label:functionality[]
+label:updated[]
+[source, cypher, role="noheader"]
+----
+RETURN $0hello
+----
+
+a| Parameters can start with extended identifier characters (such as numbers), in line with the xref:appendix/gql-conformance/index.adoc[GQL] standard.
+For more information, see xref:syntax/parameters.adoc[].
+
 a|
 label:functionality[]
 label:updated[]
@@ -222,16 +235,6 @@ MATCH SHORTEST $param GROUPS (:A)-[:R]->{0,10}(:B)
 
 a| Parameters can now be used in xref:patterns/shortest-paths.adoc[`SHORTEST` and `ANY` path patterns].
 
-a|
-label:functionality[]
-label:updated[]
-[source, cypher, role="noheader"]
-----
-RETURN $0hello
-----
-
-a| Parameters can start with extended identifier characters, in line with the xref:appendix/gql-conformance/index.adoc[GQL] standard.
-
 a|
 label:functionality[]
 label:updated[]

modules/ROOT/pages/syntax/parameters.adoc

@@ -26,7 +26,9 @@ Parameters cannot be used for the following constructs, as these form part of th
 * Relationship types; `MATCH (n)-[:$param]->(m)` is invalid.
 * Node labels; `MATCH (n:$param)` is invalid.
 
-Parameters may consist of any combination of letters and numbers, and can start with any of xref:appendix/gql-conformance/index.adoc[GQL's] extended character identifiers.
+Parameter names can start with and contain underscores, letters, numbers, and combining marks such as accents (e.g., `é`).
+Currency symbols (e.g., `$` and `€`), non-printable Unicode control characters that only affect formatting (e.g., `\t` for Tab), punctuation (e.g., `!`), and whitespaces are not allowed in any position of a parameter name.
+For example, `$héllo`, `$0param`, and `$_param` are valid, while `$€value`, `$hello!`, and `$bad param` are not.
 
 Setting parameters when running a query is dependent on the client environment.
 For example: