remove pre-4.2 logic from change streams, aggregate, and server

Author: dariakp

src/cursor/change_stream_cursor.ts

@@ -93,7 +93,7 @@ export class ChangeStreamCursor<
       } else {
         options.resumeAfter = this.resumeToken;
       }
-    } else if (this.startAtOperationTime != null && maxWireVersion(this.server) >= 7) {
+    } else if (this.startAtOperationTime != null) {
       options.startAtOperationTime = this.startAtOperationTime;
     }
 
@@ -145,8 +145,7 @@ export class ChangeStreamCursor<
     if (
       this.startAtOperationTime == null &&
       this.changeStreamCursorOptions.resumeAfter == null &&
-      this.changeStreamCursorOptions.startAfter == null &&
-      this.maxWireVersion >= 7
+      this.changeStreamCursorOptions.startAfter == null
     ) {
       this.startAtOperationTime = response.operationTime;
     }

src/operations/aggregate.ts

@@ -4,14 +4,13 @@ import { CursorResponse, ExplainedCursorResponse } from '../cmap/wire_protocol/r
 import { type CursorTimeoutMode } from '../cursor/abstract_cursor';
 import { MongoInvalidArgumentError } from '../error';
 import { type ExplainOptions } from '../explain';
-import { maxWireVersion, type MongoDBNamespace } from '../utils';
+import { type MongoDBNamespace } from '../utils';
 import { WriteConcern } from '../write_concern';
 import { type CollationOptions, CommandOperation, type CommandOperationOptions } from './command';
 import { Aspect, defineAspects, type Hint } from './operation';
 
 /** @internal */
 export const DB_AGGREGATE_COLLECTION = 1 as const;
-const MIN_WIRE_VERSION_$OUT_READ_CONCERN_SUPPORT = 8;
 
 /** @public */
 export interface AggregateOptions extends Omit<CommandOperationOptions, 'explain'> {
@@ -109,13 +108,8 @@ export class AggregateOperation extends CommandOperation<CursorResponse> {
 
   override buildCommandDocument(connection: Connection): Document {
     const options = this.options;
-    const serverWireVersion = maxWireVersion(connection);
     const command: Document = { aggregate: this.target, pipeline: this.pipeline };
 
-    if (this.hasWriteStage && serverWireVersion < MIN_WIRE_VERSION_$OUT_READ_CONCERN_SUPPORT) {
-      this.readConcern = undefined;
-    }
-
     if (this.hasWriteStage && this.writeConcern) {
       WriteConcern.apply(command, this.writeConcern);
     }

src/sdam/server.ts

@@ -414,7 +414,7 @@ export class Server extends TypedEventEmitter<ServerEvents> {
     } else {
       if (isSDAMUnrecoverableError(error)) {
         if (shouldHandleStateChangeError(this, error)) {
-          const shouldClearPool = maxWireVersion(this) <= 7 || isNodeShuttingDownError(error);
+          const shouldClearPool = isNodeShuttingDownError(error);
           if (this.loadBalanced && connection && shouldClearPool) {
             this.pool.clear({ serviceId: connection.serviceId });
           }