diff --git a/app/build.gradle b/app/build.gradle
index 2e3b20f..ea51594 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -34,6 +34,7 @@ dependencies {
     implementation "com.android.support:recyclerview-v7:$rootProject.supportLibraryVersion"
 
     implementation "io.reactivex.rxjava2:rxjava:$rootProject.rxjava"
+    implementation "io.reactivex:rxjava:$rootProject.rxjava1"
     implementation "io.reactivex.rxjava2:rxandroid:$rootProject.rxandroid"
     implementation "io.reactivex:rxjava-math:$rootProject.rxjavaMath"
 
diff --git a/build.gradle b/build.gradle
index c3ab467..71acc4b 100644
--- a/build.gradle
+++ b/build.gradle
@@ -7,7 +7,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.0.1'
+        classpath 'com.android.tools.build:gradle:4.0.0'
         
 
         // NOTE: Do not place your application dependencies here; they belong
@@ -46,6 +46,7 @@ ext {
     espressoVersion = '3.0.1'
     butterKnfie = '8.8.1'
     rxjava = '2.1.9'
+    rxjava1 = '1.3.8'
     rxandroid = '2.0.1'
     rxjavaMath = '1.0.0'
     rxbinding = '2.0.0'