diff --git a/types/log4js.d.ts b/types/log4js.d.ts
index 7d651c2c..ec26cc1e 100644
--- a/types/log4js.d.ts
+++ b/types/log4js.d.ts
@@ -263,14 +263,9 @@ export interface CustomAppender {
 }
 
 export interface AppenderModule {
-  configure: (config: Config, layouts: LayoutsParam) => AppenderGenerator;
+  configure: (config: Config, layouts: LayoutsParam) => AppenderFunction;
 }
 
-export type AppenderGenerator = (
-  layout: LayoutFunction,
-  timezoneOffset?: string
-) => AppenderFunction;
-
 export type AppenderFunction = (loggingEvent: LoggingEvent) => void;
 
 // TODO: Actually add types here...
@@ -321,7 +316,7 @@ export interface Levels {
   FATAL: Level;
   OFF: Level;
   levels: Level[];
-  getLevel(level: Level | string, defaultLevel: Level): Level;
+  getLevel(level: Level | string, defaultLevel?: Level): Level;
   addLevels(customLevels: object): void;
 }
 
diff --git a/types/test.ts b/types/test.ts
index a2f0fafc..b0c8d4ed 100644
--- a/types/test.ts
+++ b/types/test.ts
@@ -133,7 +133,7 @@ log4js.connectLogger(logger2, {
 
 //support for passing in an appender module
 log4js.configure({
-  appenders: { thing: { type: { configure: () => {} }}},
+  appenders: { thing: { type: { configure: () => () => {} }}},
   categories: { default: { appenders: ['thing'], level: 'debug'}}
 });