diff --git a/usbSerialForAndroid/build.gradle b/usbSerialForAndroid/build.gradle
index 5aa0170..bf1bde1 100644
--- a/usbSerialForAndroid/build.gradle
+++ b/usbSerialForAndroid/build.gradle
@@ -7,19 +7,14 @@ android {
     defaultConfig {
         minSdkVersion 17
         targetSdkVersion 28
+        consumerProguardFiles 'proguard-rules.pro'
+        
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
         testInstrumentationRunnerArguments = [                    // Raspi   Windows   LinuxVM   ...
                 'rfc2217_server_host': '192.168.0.100',
                 'rfc2217_server_nonstandard_baudrates': 'true',   // true    false     false
         ]
     }
-
-    buildTypes {
-        release {
-            minifyEnabled false
-            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
-        }
-    }
 }
 
 dependencies {
diff --git a/usbSerialForAndroid/proguard-rules.pro b/usbSerialForAndroid/proguard-rules.pro
new file mode 100644
index 0000000..102a90a
--- /dev/null
+++ b/usbSerialForAndroid/proguard-rules.pro
@@ -0,0 +1 @@
+-keep class com.hoho.android.usbserial.driver.* { *; }
diff --git a/usbSerialForAndroid/publishToMavenLocal.gradle b/usbSerialForAndroid/publishToMavenLocal.gradle
index 1212e0d..a007e7b 100644
--- a/usbSerialForAndroid/publishToMavenLocal.gradle
+++ b/usbSerialForAndroid/publishToMavenLocal.gradle
@@ -5,7 +5,7 @@ publishing {
         maven(MavenPublication) {
             groupId 'com.github.mik3y'
             artifactId 'usb-serial-for-android'
-            version '1.x.0'
+            version '2.1.0a'
             afterEvaluate {
                 artifact androidSourcesJar
                 artifact bundleReleaseAar