diff --git a/nodemailer/nodemailer-tests.ts.tscparams b/nodemailer/nodemailer-tests.ts.tscparams
deleted file mode 100644
index e16c76dff8..0000000000
--- a/nodemailer/nodemailer-tests.ts.tscparams
+++ /dev/null
@@ -1 +0,0 @@
-""
diff --git a/nodemailer/nodemailer.d.ts b/nodemailer/nodemailer.d.ts
index 7d77a58ae5..c95aee99f9 100644
--- a/nodemailer/nodemailer.d.ts
+++ b/nodemailer/nodemailer.d.ts
@@ -17,8 +17,8 @@ declare class Transport {
 	options: Object;
 	transportType: string;
 	sendMailWithTransport(emailMessage: MailComposer, callback?: (err: Error) => any): any;
-	useDKIM(dkim: DKIMOptions);
-	close(callback?: (err: Error) => any);
+	useDKIM(dkim: DKIMOptions): void;
+	close(callback?: (err: Error) => any): any;
 	sendMail(message: MailComposer, callback?: (err: Error) => any): any;
 	send_mail(message:MailComposer, callback?: (err: Error) => any): any;
 }
diff --git a/nodemailer/nodemailer.d.ts.tscparams b/nodemailer/nodemailer.d.ts.tscparams
deleted file mode 100644
index e16c76dff8..0000000000
--- a/nodemailer/nodemailer.d.ts.tscparams
+++ /dev/null
@@ -1 +0,0 @@
-""