diff --git a/types/theo/index.d.ts b/types/theo/index.d.ts
index d60a797159..de15c0238a 100644
--- a/types/theo/index.d.ts
+++ b/types/theo/index.d.ts
@@ -1,9 +1,9 @@
-// Type definitions for theo 8.1
+// Type definitions for Theo 8.1
 // Project: https://github.com/salesforce-ux/theo
 // Definitions by: Pete Petrash <https://github.com/petekp>
 //                 Niko Laitinen <https://github.com/laitine>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.2
+// TypeScript Version: 2.3
 
 import { Collection, Map, List, OrderedMap } from "immutable";
 
@@ -35,21 +35,16 @@ export type Format =
     | "android.xml"
     | "aura.tokens";
 
-export function convert(options: ConvertOptions): Promise<string>;
-export function convertSync(options: ConvertOptions): string;
-export function registerFormat(
-    name: string,
-    format: FormatResultFn | string
-): void;
-export function registerTransform(
-    name: string,
-    valueTransforms: string[]
-): void;
-export function registerValueTransform(
-    name: string,
-    predicate: (prop: Prop) => boolean,
-    transform: (prop: Prop) => string | number
-): void;
+export type Transform = "raw" | "ios" | "android" | "web";
+
+export type ValueTransform =
+    | "color/rgb"
+    | "color/hex"
+    | "color/hex8rgba"
+    | "color/hex8argb"
+    | "percentage/float"
+    | "relative/pixel"
+    | "relative/pixelValue";
 
 export type Prop = Map<StyleProperty, string | number>;
 export type Props = List<Prop>;
@@ -78,8 +73,8 @@ export interface ConvertOptions {
     resolveMetaAliases?: boolean;
 }
 
-export interface TransformOptions {
-    type?: string;
+export interface TransformOptions<T extends string = never> {
+    type?: Transform | T;
     file: string;
     data?: string;
 }
@@ -91,3 +86,19 @@ export interface FormatOptions {
         transformPropName?: (name: string) => string
     ) => void;
 }
+
+export function convert(options: ConvertOptions): Promise<string>;
+export function convertSync(options: ConvertOptions): string;
+export function registerFormat<T extends string = never>(
+    name: Format | T,
+    format: FormatResultFn | string
+): void;
+export function registerTransform<T extends string = never>(
+    name: Transform | T,
+    valueTransforms: ValueTransform[] | T[]
+): void;
+export function registerValueTransform<T extends string = never>(
+    name: ValueTransform | T,
+    predicate: (prop: Prop) => boolean,
+    transform: (prop: Prop) => string | number
+): void;
diff --git a/types/theo/tslint.json b/types/theo/tslint.json
index 3db14f85ea..71ee04c4e1 100644
--- a/types/theo/tslint.json
+++ b/types/theo/tslint.json
@@ -1 +1,6 @@
-{ "extends": "dtslint/dt.json" }
+{
+    "extends": "dtslint/dt.json",
+    "rules": {
+        "no-unnecessary-generics": false
+    }
+}