diff --git a/.idea/caches/build_file_checksums.ser b/.idea/caches/build_file_checksums.ser
index 365009f..e282ac2 100644
Binary files a/.idea/caches/build_file_checksums.ser and b/.idea/caches/build_file_checksums.ser differ
diff --git a/.idea/caches/gradle_models.ser b/.idea/caches/gradle_models.ser
index a5fcf78..81d1e35 100644
Binary files a/.idea/caches/gradle_models.ser and b/.idea/caches/gradle_models.ser differ
diff --git a/SerialPortLibrary/build.gradle b/SerialPortLibrary/build.gradle
index f90eff0..e280a8b 100644
--- a/SerialPortLibrary/build.gradle
+++ b/SerialPortLibrary/build.gradle
@@ -34,6 +34,6 @@ dependencies {
     androidTestImplementation('com.android.support.test.espresso:espresso-core:2.2.2', {
         exclude group: 'com.android.support', module: 'support-annotations'
     })
-    implementation 'com.android.support:appcompat-v7:23.4.0'
+    implementation 'com.android.support:appcompat-v7:28.0.0'
     testImplementation 'junit:junit:4.12'
 }
diff --git a/app/build.gradle b/app/build.gradle
index b1a8aff..dd70da2 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -25,7 +25,7 @@ dependencies {
         exclude group: 'com.android.support', module: 'support-annotations'
     })
     implementation project(':SerialPortLibrary')
-    implementation 'com.android.support:appcompat-v7:23.4.0'
+    implementation 'com.android.support:appcompat-v7:28.0.0'
     implementation 'com.android.support.constraint:constraint-layout:1.0.2'
     testImplementation 'junit:junit:4.12'