diff --git a/build.gradle b/build.gradle
index 418dc51..0218a87 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,13 +1,13 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 buildscript {
-    ext.kotlin_version = '1.4.21'
+    ext.kotlin_version = '1.5.21'
     repositories {
         google()
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.2'
+        classpath 'com.android.tools.build:gradle:7.0.1'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
diff --git a/core/bintray.gradle b/core/bintray.gradle
deleted file mode 100644
index 1cd0b15..0000000
--- a/core/bintray.gradle
+++ /dev/null
@@ -1,68 +0,0 @@
-group = PROJ_GROUP
-version = PROJ_VERSION
-project.archivesBaseName = PROJ_ARTIFACTID
-
-apply plugin: 'com.jfrog.bintray'
-apply plugin: 'maven-publish'
-
-task sourcesJar(type: Jar) {
-    from android.sourceSets.main.java.srcDirs
-    classifier = 'sources'
-}
-
-artifacts {
-    archives sourcesJar
-}
-
-def pomConfig = {
-    licenses {
-        license {
-            name "The Apache Software License, Version 2.0"
-            url "http://www.apache.org/licenses/LICENSE-2.0.txt"
-            distribution "repo"
-        }
-    }
-    developers {
-        developer {
-            id DEVELOPER_ID
-            name DEVELOPER_NAME
-            email DEVELOPER_EMAIL
-        }
-    }
-}
-
-publishing {
-    publications {
-        mavenJava(MavenPublication) {
-            artifactId PROJ_ARTIFACTID
-
-            pom{
-                packaging 'aar'
-            }
-            pom.withXml {
-                def root = asNode()
-                root.appendNode('description', PROJ_DESCRIPTION)
-                root.children().last() + pomConfig
-            }
-        }
-    }
-}
-
-bintray {
-    user = BINTRAY_USER
-    key = BINTRAY_KEY
-
-    configurations = ['archives']
-    publications = ['mavenJava']
-    publish = true
-
-    pkg {
-        repo = 'maven'
-        name = PROJ_NAME
-        desc = PROJ_DESCRIPTION
-        websiteUrl = PROJ_WEBSITEURL
-        vcsUrl = PROJ_VCSURL
-        licenses = ['Apache-2.0']
-        publicDownloadNumbers = true
-    }
-}
\ No newline at end of file
diff --git a/core/build.gradle b/core/build.gradle
index 3af3273..ddc4180 100644
--- a/core/build.gradle
+++ b/core/build.gradle
@@ -2,13 +2,11 @@ apply plugin: 'com.android.library'
 apply plugin: 'kotlin-android'
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion 31
 
     defaultConfig {
         minSdkVersion 15
-        targetSdkVersion 30
-        versionCode 1
-        versionName "1.0"
+        targetSdkVersion 31
         archivesBaseName = "core"
     }
     buildTypes {
@@ -20,36 +18,13 @@ android {
     lintOptions {
         abortOnError false
     }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
 }
 
 dependencies {
     api fileTree(dir: 'libs', include: ['*.jar'])
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
-}
-
-apply plugin: 'com.github.panpf.bintray-publish'
-
-allprojects {
-    tasks.withType(Javadoc) {
-        options.addStringOption('Xdoclint:none', '-quiet')
-        options.addStringOption('encoding', 'UTF-8')
-    }
-}
-
-buildscript {
-    repositories {
-        jcenter()
-    }
-    dependencies {
-        classpath 'com.github.panpf.bintray-publish:bintray-publish:1.0.0'
-    }
-}
-
-publish {
-    userOrg = 'sinyu890807'
-    groupId = 'org.litepal.guolindev'
-    artifactId = 'core'
-    publishVersion = '3.2.3'
-    desc = 'An Android library that allows developers to use SQLite database extremely easy'
-    website = 'https://github.com/LitePalFramework/LitePal'
 }
\ No newline at end of file
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index ad0b247..b4c1556 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.5-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-bin.zip
diff --git a/sample/build.gradle b/sample/build.gradle
index 9ffccf2..f39f838 100644
--- a/sample/build.gradle
+++ b/sample/build.gradle
@@ -2,12 +2,12 @@ apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion 31
 
     defaultConfig {
         applicationId "org.litepal.litepalsample"
         minSdkVersion 15
-        targetSdkVersion 30
+        targetSdkVersion 31
         versionCode 1
         versionName "1.0"
         testInstrumentationRunner 'androidx.test.runner.AndroidJUnitRunner'
@@ -21,6 +21,10 @@ android {
     lintOptions {
         abortOnError false
     }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
 }
 
 dependencies {