diff --git a/maxmind/index.d.ts b/maxmind/index.d.ts
index 3444d9eaa6..da45eb907b 100644
--- a/maxmind/index.d.ts
+++ b/maxmind/index.d.ts
@@ -1,9 +1,11 @@
-// Type definitions for maxmind v1.3
+// Type definitions for maxmind v2.0
 // Project: https://github.com/runk/node-maxmind
 // Definitions by: Joshua DeVinney <https://github.com/geoffreak>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
-export declare function open(database: string, opts?: Options): Reader;
+export declare function open(database: string, cb: (err: Error, reader: Reader) => void): void;
+export declare function open(database: string, opts: Options, cb: (err: Error, reader: Reader) => void): void;
+export declare function openSync(database: string, opts?: Options): Reader;
 export declare function validate(ip: string): boolean;
 
 export declare interface Reader {
diff --git a/maxmind/maxmind-tests.ts b/maxmind/maxmind-tests.ts
index 79fe2e47b6..943cd9a5d1 100644
--- a/maxmind/maxmind-tests.ts
+++ b/maxmind/maxmind-tests.ts
@@ -3,18 +3,18 @@ import * as maxmind from 'maxmind';
 // Examples from https://github.com/runk/node-maxmind/blob/master/README.md
 
 // Example 1
-var cityLookup = maxmind.open('/path/to/GeoLite2-City.mmdb');
+var cityLookup = maxmind.openSync('/path/to/GeoLite2-City.mmdb');
 var city = cityLookup.get('66.6.44.4');
 
-var orgLookup = maxmind.open('/path/to/GeoOrg.mmdb');
+var orgLookup = maxmind.openSync('/path/to/GeoOrg.mmdb');
 var organization = orgLookup.get('66.6.44.4');
 
 // Example 2
-var lookup = maxmind.open('/path/to/GeoLite2.mmdb');
+var lookup = maxmind.openSync('/path/to/GeoLite2.mmdb');
 var location = lookup.get('2001:4860:0:1001::3004:ef68');
 
 // Example 3
-var lookup = maxmind.open('/path/to/GeoLite2.mmdb', {
+var lookup = maxmind.openSync('/path/to/GeoLite2.mmdb', {
   cache: {
     max: 1000, // max items in cache
     maxAge: 1000 * 60 * 60 // life time in milliseconds