diff --git a/types/bunyan-format/bunyan-format-tests.ts b/types/bunyan-format/bunyan-format-tests.ts
index 159c3cde17..6467fccc7b 100644
--- a/types/bunyan-format/bunyan-format-tests.ts
+++ b/types/bunyan-format/bunyan-format-tests.ts
@@ -1,9 +1,10 @@
 import BunyanFormatWritable = require('bunyan-format');
+import { Writable } from 'stream';
 
-const formatOut = new BunyanFormatWritable({ outputMode: 'short' });
+const formatOut: Writable = new BunyanFormatWritable({ outputMode: 'short' });
 
-const formatOut2 = new BunyanFormatWritable({ outputMode: 'bunyan', levelInString: true });
+const formatOut2: NodeJS.WritableStream = new BunyanFormatWritable({ outputMode: 'bunyan', levelInString: true });
 
-const formatOut3 = BunyanFormatWritable({ outputMode: 'short' });
+const formatOut3: Writable = BunyanFormatWritable({ outputMode: 'short' });
 
-const formatOut4 = BunyanFormatWritable({ outputMode: 'bunyan', levelInString: true });
+const formatOut4: NodeJS.WritableStream = BunyanFormatWritable({ outputMode: 'bunyan', levelInString: true });
diff --git a/types/bunyan-format/index.d.ts b/types/bunyan-format/index.d.ts
index 867e724785..13cec4d397 100644
--- a/types/bunyan-format/index.d.ts
+++ b/types/bunyan-format/index.d.ts
@@ -3,7 +3,7 @@
 // Definitions by: Piotr Roszatycki <https://github.com/dex4er>
 //                 Ashley Abbott <https://github.com/ashpabb>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 3.6
+// TypeScript Version: 2.1
 
 /// <reference types="node" />
 
@@ -23,11 +23,14 @@ declare namespace BunyanFormatWritable {
     }
 }
 
-declare class BunyanFormatWritable extends Writable {
-    /** Creates a writable stream that formats bunyan records written to it. */
-    constructor(options: BunyanFormatWritable.Options, output?: Writable);
-}
+// tslint:disable-next-line no-empty-interface
+interface BunyanFormatWritable extends Writable {}
 
-declare function BunyanFormatWritable(options: BunyanFormatWritable.Options, output?: Writable): BunyanFormatWritable;
+declare var BunyanFormatWritable: {
+    /** Creates a writable stream that formats bunyan records written to it. */
+    (options: BunyanFormatWritable.Options, output?: Writable): BunyanFormatWritable;
+    /** Creates a writable stream that formats bunyan records written to it. */
+    new (options: BunyanFormatWritable.Options, output?: Writable): BunyanFormatWritable;
+};
 
 export = BunyanFormatWritable;