diff --git a/Gulpfile.js b/Gulpfile.js
index d66ab605b25..e65db00dcd5 100644
--- a/Gulpfile.js
+++ b/Gulpfile.js
@@ -14,7 +14,7 @@ const { src, dest, task, parallel, series, watch } = require("gulp");
 const { append, transform } = require("gulp-insert");
 const { browserify } = require("./scripts/build/browserify");
 const { prependFile } = require("./scripts/build/prepend");
-const { exec, readJson, needsUpdate, getDiffTool, getDirSize, flatten, rm } = require("./scripts/build/utils");
+const { exec, readJson, needsUpdate, getDiffTool, getDirSize, rm } = require("./scripts/build/utils");
 const { runConsoleTests, cleanTestDirs, writeTestConfigFile, refBaseline, localBaseline, refRwcBaseline, localRwcBaseline } = require("./scripts/build/tests");
 const { buildProject, cleanProject, watchProject } = require("./scripts/build/projects");
 const cmdLineOptions = require("./scripts/build/options");
@@ -114,21 +114,8 @@ const localPreBuild = parallel(generateLibs, series(buildScripts, generateDiagno
 const preBuild = cmdLineOptions.lkg ? lkgPreBuild : localPreBuild;
 
 const buildServices = (() => {
-    // flatten the services project
-    const flattenServicesConfig = async () => flatten("src/services/tsconfig.json", "built/local/typescriptServices.tsconfig.json", {
-        compilerOptions: {
-            "removeComments": false,
-            "stripInternal": true,
-            "declarationMap": false,
-            "outFile": "typescriptServices.out.js"
-        }
-    });
-
     // build typescriptServices.out.js
-    const buildTypescriptServicesOut = () => buildProject("built/local/typescriptServices.tsconfig.json", cmdLineOptions);
-
-    // build typescriptServices/typescriptServices.js
-    const buildTypescriptServicesOut1 = () => buildProject("src/typescriptServices/tsconfig.json", { ...cmdLineOptions, lkg: false });
+    const buildTypescriptServicesOut = () => buildProject("src/typescriptServices/tsconfig.json", cmdLineOptions);
 
     // create typescriptServices.js
     const createTypescriptServicesJs = () => src("built/local/typescriptServices.out.js")
@@ -139,15 +126,6 @@ const buildServices = (() => {
         .pipe(sourcemaps.write(".", { includeContent: false, destPath: "built/local" }))
         .pipe(dest("built/local"));
 
-    // create typescriptServices1.js
-    const createTypescriptServicesJs1 = () => src("built/local/typescriptServices/typescriptServices.js")
-        .pipe(newer("built/local/typescriptServices1.js"))
-        .pipe(sourcemaps.init({ loadMaps: true }))
-        .pipe(prependFile(copyright))
-        .pipe(rename("typescriptServices1.js"))
-        .pipe(sourcemaps.write(".", { includeContent: false, destPath: "built/local" }))
-        .pipe(dest("built/local"));
-
     // create typescriptServices.d.ts
     const createTypescriptServicesDts = () => src("built/local/typescriptServices.out.d.ts")
         .pipe(newer("built/local/typescriptServices.d.ts"))
@@ -156,14 +134,6 @@ const buildServices = (() => {
         .pipe(rename("typescriptServices.d.ts"))
         .pipe(dest("built/local"));
 
-    // create typescriptServices1.d.ts
-    const createTypescriptServicesDts1 = () => src("built/local/typescriptServices/typescriptServices.d.ts")
-        .pipe(newer("built/local/typescriptServices1.d.ts"))
-        .pipe(prependFile(copyright))
-        .pipe(transform(content => content.replace(/^(\s*)(export )?const enum (\S+) {(\s*)$/gm, "$1$2enum $3 {$4")))
-        .pipe(rename("typescriptServices1.d.ts"))
-        .pipe(dest("built/local"));
-
     // create typescript.js
     const createTypescriptJs = () => src("built/local/typescriptServices.js")
         .pipe(newer("built/local/typescript.js"))
@@ -172,14 +142,6 @@ const buildServices = (() => {
         .pipe(sourcemaps.write(".", { includeContent: false, destPath: "built/local" }))
         .pipe(dest("built/local"));
 
-    // create typescript1.js
-    const createTypescriptJs1 = () => src("built/local/typescriptServices1.js")
-        .pipe(newer("built/local/typescript1.js"))
-        .pipe(sourcemaps.init({ loadMaps: true }))
-        .pipe(rename("typescript1.js"))
-        .pipe(sourcemaps.write(".", { includeContent: false, destPath: "built/local" }))
-        .pipe(dest("built/local"));
-
     // create typescript.d.ts
     const createTypescriptDts = () => src("built/local/typescriptServices.d.ts")
         .pipe(newer("built/local/typescript.d.ts"))
@@ -187,13 +149,6 @@ const buildServices = (() => {
         .pipe(rename("typescript.d.ts"))
         .pipe(dest("built/local"));
 
-    // create typescript1.d.ts
-    const createTypescriptDts1 = () => src("built/local/typescriptServices1.d.ts")
-        .pipe(newer("built/local/typescript1.d.ts"))
-        .pipe(append("\nexport = ts;"))
-        .pipe(rename("typescript1.d.ts"))
-        .pipe(dest("built/local"));
-
     // create typescript_standalone.d.ts
     const createTypescriptStandaloneDts = () => src("built/local/typescriptServices.d.ts")
         .pipe(newer("built/local/typescript_standalone.d.ts"))
@@ -201,28 +156,13 @@ const buildServices = (() => {
         .pipe(rename("typescript_standalone.d.ts"))
         .pipe(dest("built/local"));
 
-    // create typescript_standalone.d.ts
-    const createTypescriptStandaloneDts1 = () => src("built/local/typescriptServices1.d.ts")
-        .pipe(newer("built/local/typescript_standalone1.d.ts"))
-        .pipe(transform(content => content.replace(/declare (namespace|module) ts/g, 'declare module "typescript"')))
-        .pipe(rename("typescript_standalone1.d.ts"))
-        .pipe(dest("built/local"));
-
     return series(
-        flattenServicesConfig,
         buildTypescriptServicesOut,
         createTypescriptServicesJs,
         createTypescriptServicesDts,
         createTypescriptJs,
         createTypescriptDts,
         createTypescriptStandaloneDts,
-        //localPreBuild,
-        //buildTypescriptServicesOut1,
-        //createTypescriptServicesJs1,
-        //createTypescriptServicesDts1,
-        //createTypescriptJs1,
-        //createTypescriptDts1,
-        //createTypescriptStandaloneDts1,
     );
 })();
 task("services", series(preBuild, buildServices));
@@ -236,20 +176,13 @@ const cleanServices = async () => {
         await cleanProject("built/local/typescriptServices.tsconfig.json");
     }
     await del([
-        "built/local/typescriptServices.tsconfig.json",
         "built/local/typescriptServices.out.js",
         "built/local/typescriptServices.out.d.ts",
+        "built/local/typescriptServices.out.tsbuildinfo",
         "built/local/typescriptServices.js",
         "built/local/typescript.js",
         "built/local/typescript.d.ts",
-        "built/local/typescript_standalone.d.ts",
-        "built/local/typescriptServices/typescriptServices.js",
-        "built/local/typescriptServices/typescriptServices.js.map",
-        "built/local/typescriptServices/typescriptServices.d.ts",
-        "built/local/typescriptServices1.js",
-        "built/local/typescript1.js",
-        "built/local/typescript1.d.ts",
-        "built/local/typescript_standalone1.d.ts",
+        "built/local/typescript_standalone.d.ts"
     ]);
 };
 cleanTasks.push(cleanServices);
@@ -305,23 +238,8 @@ task("watch-min").flags = {
 }
 
 const buildLssl = (() => {
-    // flatten the server project
-    const flattenTsServerProject = async () => flatten("src/tsserver/tsconfig.json", "built/local/tsserverlibrary.tsconfig.json", {
-        exclude: ["src/tsserver/server.ts"],
-        compilerOptions: {
-            "removeComments": false,
-            "stripInternal": true,
-            "declaration": true,
-            "declarationMap": false,
-            "outFile": "tsserverlibrary.out.js"
-        }
-    });
-
     // build tsserverlibrary.out.js
-    const buildServerLibraryOut = () => buildProject("built/local/tsserverlibrary.tsconfig.json", cmdLineOptions);
-
-    // build tsserverlibrary1.out.js
-    const buildServerLibraryOut1 = () => buildProject("src/tsserverlibrary/tsconfig.json", { ...cmdLineOptions, lkg: false });
+    const buildServerLibraryOut = () => buildProject("src/tsserverlibrary/tsconfig.json", cmdLineOptions);
 
     // create tsserverlibrary.js
     const createServerLibraryJs = () => src("built/local/tsserverlibrary.out.js")
@@ -332,15 +250,6 @@ const buildLssl = (() => {
         .pipe(sourcemaps.write(".", { includeContent: false, destPath: "built/local" }))
         .pipe(dest("built/local"));
 
-    // create tsserverlibrary1.js
-    const createServerLibraryJs1 = () => src("built/local/tsserverlibrary/tsserverlibrary.js")
-        .pipe(newer("built/local/tsserverlibrary1.js"))
-        .pipe(sourcemaps.init({ loadMaps: true }))
-        .pipe(prependFile(copyright))
-        .pipe(rename("tsserverlibrary1.js"))
-        .pipe(sourcemaps.write(".", { includeContent: false, destPath: "built/local" }))
-        .pipe(dest("built/local"));
-
     // create tsserverlibrary.d.ts
     const createServerLibraryDts = () => src("built/local/tsserverlibrary.out.d.ts")
         .pipe(newer("built/local/tsserverlibrary.d.ts"))
@@ -350,24 +259,10 @@ const buildLssl = (() => {
         .pipe(rename("tsserverlibrary.d.ts"))
         .pipe(dest("built/local"));
 
-    // create tsserverlibrary1.d.ts
-    const createServerLibraryDts1 = () => src("built/local/tsserverlibrary/tsserverlibrary.d.ts")
-        .pipe(newer("built/local/tsserverlibrary1.d.ts"))
-        .pipe(prependFile(copyright))
-        .pipe(transform(content => content.replace(/^(\s*)(export )?const enum (\S+) {(\s*)$/gm, "$1$2enum $3 {$4")))
-        .pipe(append("\nexport = ts;\nexport as namespace ts;"))
-        .pipe(rename("tsserverlibrary1.d.ts"))
-        .pipe(dest("built/local"));
-
     return series(
-        flattenTsServerProject,
         buildServerLibraryOut,
         createServerLibraryJs,
         createServerLibraryDts,
-        //localPreBuild,
-        //buildServerLibraryOut1,
-        //createServerLibraryJs1,
-        //createServerLibraryDts1
     );
 })();
 task("lssl", series(preBuild, buildLssl));
@@ -381,9 +276,9 @@ const cleanLssl = async () => {
         await cleanProject("built/local/tsserverlibrary.tsconfig.json");
     }
     await del([
-        "built/local/tsserverlibrary.tsconfig.json",
         "built/local/tsserverlibrary.out.js",
         "built/local/tsserverlibrary.out.d.ts",
+        "built/local/tsserverlibrary.out.tsbuildinfo",
         "built/local/tsserverlibrary.js",
         "built/local/tsserverlibrary.d.ts",
         "built/local/tsserverlibrary/tsserverlibrary.js",
diff --git a/src/cancellationToken/tsconfig.json b/src/cancellationToken/tsconfig.json
index 6d9e0af7724..6d27fe45cf3 100644
--- a/src/cancellationToken/tsconfig.json
+++ b/src/cancellationToken/tsconfig.json
@@ -7,6 +7,7 @@
         "declaration": false,
         "declarationMap": false,
         "removeComments": true,
+        "incremental": false,
         "module": "commonjs",
         "types": [
             "node"
diff --git a/src/tsconfig-library-base.json b/src/tsconfig-library-base.json
index 1ec945796ee..46de44a48ff 100644
--- a/src/tsconfig-library-base.json
+++ b/src/tsconfig-library-base.json
@@ -2,7 +2,9 @@
     "extends": "./tsconfig-base",
     "compilerOptions": {
         "declarationMap": false,
+        "sourceMap":  false,
         "composite": false,
+        "incremental":  true,
         "declaration": true,
         "stripInternal":  true
     }
diff --git a/src/tsconfig-noncomposite-base.json b/src/tsconfig-noncomposite-base.json
index 569269f7562..879a038f5a0 100644
--- a/src/tsconfig-noncomposite-base.json
+++ b/src/tsconfig-noncomposite-base.json
@@ -3,6 +3,7 @@
     "compilerOptions": {
         "declaration": false,
         "declarationMap": false,
-        "composite":  false
+        "composite": false,
+        "incremental": true
     }
 }
diff --git a/src/watchGuard/tsconfig.json b/src/watchGuard/tsconfig.json
index aafa2270297..b169f00c95b 100644
--- a/src/watchGuard/tsconfig.json
+++ b/src/watchGuard/tsconfig.json
@@ -2,6 +2,7 @@
     "extends": "../tsconfig-noncomposite-base",
     "compilerOptions": {
         "removeComments": true,
+        "incremental":  false,
         "outFile": "../../built/local/watchGuard.js",
         "types": [
             "node"