diff --git a/README.md b/README.md
index 5c84ec9..d97a187 100644
--- a/README.md
+++ b/README.md
@@ -60,7 +60,8 @@ launcher.authenticator.getAuth("email", "password").then(auth => {
 | `options.proxy.password` | String | Password for the proxy.                                                                   | False    |
 
 ##### Note
-If you are loading up a client outside of vanilla Minecraft and Forge (Optifine for an example), you'll need to download the needed files yourself.
+If you are loading up a client outside of vanilla Minecraft or Forge (Optifine and for an example), you'll need to download the needed files yourself
+if you don't provide downloads url downloads like Forge and Fabric. Still need to provide the version jar.
 
 #### launcher.authenticator Functions 
 
diff --git a/components/handler.js b/components/handler.js
index f23ea1f..9e036ee 100644
--- a/components/handler.js
+++ b/components/handler.js
@@ -246,14 +246,20 @@ module.exports.getClasses = function (options, version) {
 
         if(options.version.custom) {
             const customJarJson = require(path.join(options.root, 'versions', options.version.custom, `${options.version.custom}.json`));
-            customJarJson.libraries.map(library => {
+            await Promise.all(customJarJson.libraries.map(async library => {
                 const lib = library.name.split(':');
 
                 const jarPath = path.join(options.root, 'libraries', `${lib[0].replace(/\./g, '/')}/${lib[1]}/${lib[2]}`);
                 const name = `${lib[1]}-${lib[2]}.jar`;
 
+                if(!fs.existsSync(path.join(jarPath, name))) {
+                    if(library.url) {
+                        const url = `${library.url}${lib[0].replace(/\./g, '/')}/${lib[1]}/${lib[2]}/${lib[1]}-${lib[2]}.jar`;
+                        await downloadAsync(url, jarPath, name);
+                    }
+                }
                 libs.push(`${jarPath}/${name}`);
-            })
+            }));
         }
 
         await Promise.all(version.libraries.map(async (_lib) => {
diff --git a/components/launcher.js b/components/launcher.js
index e827c08..6a5aa33 100644
--- a/components/launcher.js
+++ b/components/launcher.js
@@ -65,8 +65,9 @@ module.exports = async function (options) {
         classPaths.push(`${options.forge.path || options.forge}${separator}${forge.paths.join(separator)}${separator}${classes.join(separator)};${mcPath}`);
         classPaths.push(forge.forge.mainClass)
     } else {
+        const file = custom || versionFile;
         classPaths.push(`${mcPath}${separator}${classes.join(separator)}`);
-        classPaths.push(versionFile.mainClass || custom.mainClass);
+        classPaths.push(file.mainClass);
     }
     classPaths = await handler.cleanUp(classPaths);
 
diff --git a/package.json b/package.json
index 45411cc..058ffd5 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "minecraft-launcher-core",
-  "version": "2.7.0",
+  "version": "2.8.0",
   "description": "Module that downloads Minecraft assets and runs Minecraft. Also Supports Forge",
   "main": "index.js",
   "dependencies": {