diff --git a/README.md b/README.md
index 6fca94ab43..c1cf22e0e5 100644
--- a/README.md
+++ b/README.md
@@ -56,7 +56,7 @@ You can add next maven dependency in your project:
 
 You may also need to add the following to your `project/build.gradle` file.
 
-`implementation 'com.vk:androidsdk:2.1.1`
+`implementation 'com.vk:androidsdk:2.2.0`
 
 For example, your `app/build.gradle` script will contains such dependencies:
 ```
diff --git a/dependencies.gradle b/dependencies.gradle
index 851ddefbeb..8f24d38a03 100644
--- a/dependencies.gradle
+++ b/dependencies.gradle
@@ -1,19 +1,19 @@
 ext.sdkVersions = [
-        code                            : '12',
-        name                            : '2.1.1',
+        code                            : '14',
+        name                            : '2.2.0',
 
         minSdk                          : 16,
-        targetSdk                       : 26,
+        targetSdk                       : 28,
         compileSdk                      : '28',
-        buildTools                      : '27.0.3',
+        buildTools                      : '28.0.3',
 
-        kotlin                          : '1.3.10',
-        supportLibs                     : '27.1.1',
-        okHttp                          : '3.11.0',
+        kotlin                          : '1.3.41',
+        androidX                        : '1.0.0',
+        okHttp                          : '3.12.1',
 
         picasso                         : '2.71828',
 
-        androidGradlePlugin             : '3.2.1',
+        androidGradlePlugin             : '3.5.0',
 ]
 
 ext.sdkLibraries = [
@@ -25,10 +25,10 @@ ext.sdkLibraries = [
 ]
 
 ext.sdkLibrariesSupport = [
-        supportV4                       : "com.android.support:support-v4:$sdkVersions.supportLibs",
-        support                         : "com.android.support:support-v13:$sdkVersions.supportLibs",
-        appCompat                       : "com.android.support:appcompat-v7:$sdkVersions.supportLibs",
-        recyclerView                    : "com.android.support:recyclerview-v7:$sdkVersions.supportLibs",
+        appCompat                       : "androidx.appcompat:appcompat:$sdkVersions.androidX",
+        recyclerView                    : "androidx.recyclerview:recyclerview:$sdkVersions.androidX",
+        supportV4                       : "androidx.legacy:legacy-support-v4:$sdkVersions.androidX",
+        support                         : "androidx.legacy:legacy-support-v13:$sdkVersions.androidX",
 ]
 
 ext.sdkGradlePlugins = [
diff --git a/samples/app/src/main/java/com/vk/sdk/sample/UserActivity.kt b/samples/app/src/main/java/com/vk/sdk/sample/UserActivity.kt
index fae651a743..5b6307787b 100644
--- a/samples/app/src/main/java/com/vk/sdk/sample/UserActivity.kt
+++ b/samples/app/src/main/java/com/vk/sdk/sample/UserActivity.kt
@@ -29,13 +29,12 @@ import android.content.Context
 import android.content.Intent
 import android.net.Uri
 import android.os.Bundle
-import android.support.v7.widget.LinearLayoutManager
-import android.support.v7.widget.RecyclerView
 import android.text.TextUtils
 import android.util.Log
 import android.view.LayoutInflater
 import android.view.ViewGroup
 import android.widget.*
+import androidx.recyclerview.widget.RecyclerView
 import com.squareup.picasso.Picasso
 import com.vk.api.sdk.VK
 import com.vk.api.sdk.VKApiCallback
@@ -85,7 +84,7 @@ class UserActivity: Activity() {
                     }
                 }
             }
-            override fun fail(error: VKApiExecutionException) {
+            override fun fail(error: Exception) {
                 Log.e(TAG, error.toString())
             }
         })
@@ -98,7 +97,7 @@ class UserActivity: Activity() {
                     showFriends(result)
                 }
             }
-            override fun fail(error: VKApiExecutionException) {
+            override fun fail(error: Exception) {
                 Log.e(TAG, error.toString())
             }
         })
@@ -106,7 +105,7 @@ class UserActivity: Activity() {
 
     private fun showFriends(friends: List<VKUser>) {
         val recyclerView = findViewById<RecyclerView>(R.id.friendsRV)
-        recyclerView.layoutManager = LinearLayoutManager(this, RecyclerView.HORIZONTAL, false)
+        recyclerView.layoutManager = androidx.recyclerview.widget.LinearLayoutManager(this, RecyclerView.HORIZONTAL, false)
 
         val adapter = FriendsAdapter()
         adapter.setData(friends)
@@ -143,13 +142,13 @@ class UserActivity: Activity() {
                 Toast.makeText(this@UserActivity, R.string.wall_ok, Toast.LENGTH_SHORT).show()
             }
 
-            override fun fail(error: VKApiExecutionException) {
+            override fun fail(error: Exception) {
                 Log.e(TAG, error.toString())
             }
         })
     }
 
-    inner class FriendsAdapter:  RecyclerView.Adapter<RecyclerView.ViewHolder>() {
+    inner class FriendsAdapter: RecyclerView.Adapter<RecyclerView.ViewHolder>() {
         private val friends: MutableList<VKUser> = arrayListOf()
 
         override fun onCreateViewHolder(parent: ViewGroup, viewType: Int)
diff --git a/samples/app/src/main/res/layout/activity_user.xml b/samples/app/src/main/res/layout/activity_user.xml
index 3f97df96e5..ae0d74d81c 100644
--- a/samples/app/src/main/res/layout/activity_user.xml
+++ b/samples/app/src/main/res/layout/activity_user.xml
@@ -31,7 +31,7 @@
             android:layout_gravity="center"
             android:background="@android:color/white"
             android:textColor="@color/colorPrimary" />
-        <android.support.v7.widget.RecyclerView
+        <androidx.recyclerview.widget.RecyclerView
             android:id="@+id/friendsRV"
             android:layout_width="match_parent"
             android:layout_height="150dp"
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/VK.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/VK.kt
index fbcf139481..65c79273a0 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/VK.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/VK.kt
@@ -175,10 +175,10 @@ object VK {
                 VKScheduler.runOnMainThread(Runnable {
                     callback?.success(result)
                 })
-            } catch (e: VKApiExecutionException) {
+            } catch (e: Exception) {
                 VKScheduler.runOnMainThread(Runnable {
-                    if (e.isInvalidCredentialsError) {
-                        VK.handleTokenExpired()
+                    if (e is VKApiExecutionException && e.isInvalidCredentialsError) {
+                        handleTokenExpired()
                     }
                     callback?.fail(e)
                 })
@@ -206,6 +206,14 @@ object VK {
         }
     }
 
+    /**
+     * This method returns Application ID provided in the Manifest.
+     */
+    @JvmStatic
+    fun getAppId(context: Context): Int {
+        return authManager.getAppId(context)
+    }
+
     @JvmStatic
     fun clearAccessToken(context: Context) {
         authManager.getPreferences(context).edit().clear().apply()
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/VKApiCallback.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/VKApiCallback.kt
index 4331ff25dd..14767b77bc 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/VKApiCallback.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/VKApiCallback.kt
@@ -24,13 +24,11 @@
 
 package com.vk.api.sdk
 
-import com.vk.api.sdk.exceptions.VKApiExecutionException
-
 /**
  * Callback for vk api requests
  * Get response here from VK.execute
  */
 interface VKApiCallback<in T> {
     fun success(result: T)
-    fun fail(error: VKApiExecutionException)
+    fun fail(error: Exception)
 }
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/VKApiManager.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/VKApiManager.kt
index f1640e43b0..d4b320cb71 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/VKApiManager.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/VKApiManager.kt
@@ -65,17 +65,6 @@ open class VKApiManager(val config: VKApiConfig) {
         return executeWithExceptionAdjust(cc)
     }
 
-    fun <T> execute(call: OauthHttpUrlPostCall, parser: VKApiResponseParser<T>? = null): T {
-        var cc: ChainCall<T> = OAuthHttpUrlChainCall(this, executor, call, parser)
-        if (call.retryCountOnBackendError != 0) {
-            cc = InternalErrorRetryChainCall(this, call.retryCountOnBackendError, cc)
-        }
-        if (call.retryCountOnBackendError != 0) {
-            cc = ValidationHandlerChainCall(this, call.retryCountOnBackendError, cc)
-        }
-        return executeWithExceptionAdjust(cc)
-    }
-
     protected open fun <T> wrapCall(call: VKMethodCall, chainCall: ChainCall<T>): ChainCall<T> {
         var cc: ChainCall<T> = if (call.skipValidation) {
             chainCall
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/VKMethodCall.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/VKMethodCall.kt
index 348a36571c..303f285acb 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/VKMethodCall.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/VKMethodCall.kt
@@ -35,7 +35,7 @@ open class VKMethodCall {
             private set
         var args: MutableMap<String,String> = LinkedHashMap()
             private set
-        var retryCount: Int = Int.MAX_VALUE
+        var retryCount: Int = DEFAULT_RETRY_COUNT
             private set
         var skipValidation: Boolean = false
             private set
@@ -48,6 +48,7 @@ open class VKMethodCall {
         open fun version(version: String) = apply { this.version = version }
         open fun args(args: Map<String,String>) = apply { this.args.putAll(args) }
         open fun args(key: String, value: String) = apply { this.args[key] = value }
+        open fun args(key: String, value: Boolean) = apply { this.args[key] = if (value) "1" else "0" }
         open fun args(key: String, value: Any) = apply { this.args[key] = value.toString() }
         open fun retryCount(count: Int) = apply { this.retryCount = count }
         open fun skipValidation(skip: Boolean) = apply { this.skipValidation = skip }
@@ -70,4 +71,8 @@ open class VKMethodCall {
         this.retryCount = b.retryCount
         this.skipValidation = b.skipValidation
     }
+
+    companion object {
+        private const val DEFAULT_RETRY_COUNT = 4
+    }
 }
\ No newline at end of file
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/VKScheduler.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/VKScheduler.kt
index cbd749673a..d8a0045ba8 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/VKScheduler.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/VKScheduler.kt
@@ -2,6 +2,7 @@ package com.vk.api.sdk
 
 import android.os.Handler
 import android.os.Looper
+import java.util.concurrent.ExecutorService
 import java.util.concurrent.Executors
 import java.util.concurrent.atomic.AtomicInteger
 
@@ -19,10 +20,11 @@ internal object VKScheduler {
      * Intended to perform network requests: makes new thread every time if cached threads are busy
      * or reuse idle thread.
      */
-    @JvmField
-    val networkExecutor = Executors.newFixedThreadPool(NETWORK_THREADS_COUNT) { runnable ->
-        Thread(runnable, "vk-network-thread-${counter.getAndIncrement()}")
-    }!!
+    val networkExecutor: ExecutorService by lazy {
+        Executors.newFixedThreadPool(NETWORK_THREADS_COUNT) { runnable ->
+            Thread(runnable, "vk-api-network-thread-${counter.getAndIncrement()}")
+        }
+    }
 
     @JvmOverloads
     @JvmStatic
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/auth/VKAccessToken.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/auth/VKAccessToken.kt
index 2f01b2e263..d33236e47a 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/auth/VKAccessToken.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/auth/VKAccessToken.kt
@@ -108,7 +108,7 @@ class VKAccessToken(params: Map<String, String?>) {
                 return null
             }
             val vkTokenBundle = bundle.getBundle(VK_ACCESS_TOKEN_KEY) ?: return null
-            val tokenParams = HashMap<String, String>()
+            val tokenParams = HashMap<String, String?>()
             for (key in vkTokenBundle.keySet()) {
                 tokenParams[key] = vkTokenBundle.getString(key)
             }
@@ -119,7 +119,7 @@ class VKAccessToken(params: Map<String, String?>) {
             if (preferences == null) {
                 return null
             }
-            val tokenParams = HashMap<String, String>()
+            val tokenParams = HashMap<String, String?>()
             for (key in preferences.all.keys) {
                 tokenParams[key] = preferences.getString(key, "")
             }
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/auth/VKAuthManager.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/auth/VKAuthManager.kt
index 0042f77e77..fe1a5450d2 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/auth/VKAuthManager.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/auth/VKAuthManager.kt
@@ -35,7 +35,7 @@ import java.util.*
 
 internal class VKAuthManager {
     fun login(activity: Activity, scopes: Collection<VKScope>) {
-        val params = VKAuthParams(getAppId(activity), scopes)
+        val params = VKAuthParams(getAppId(activity), scope = scopes)
         if (VKUtils.isAppInstalled(activity, VK_APP_PACKAGE_ID) && VKUtils.isIntentAvailable(activity, VK_APP_AUTH_ACTION)) {
             startAuthActivity(activity, params)
         } else {
@@ -57,10 +57,15 @@ internal class VKAuthManager {
     }
 
     fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?, callback: VKAuthCallback, context: Context): Boolean {
-        if (requestCode != VK_APP_AUTH_CODE || data == null) {
+        if (requestCode != VK_APP_AUTH_CODE) {
             return false
         }
 
+        if (data == null) {
+            callback.onLoginFailed(VKAuthCallback.AUTH_CANCELED)
+            return true
+        }
+
         val result = processResult(data)
         if (resultCode != Activity.RESULT_OK || result == null || result.isError) {
             callback.onLoginFailed(VKAuthCallback.AUTH_CANCELED)
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/auth/VKAuthParams.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/auth/VKAuthParams.kt
index c1e6d042f9..7cd6eed584 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/auth/VKAuthParams.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/auth/VKAuthParams.kt
@@ -27,7 +27,7 @@ package com.vk.api.sdk.auth
 import android.os.Bundle
 import java.util.HashSet
 
-class VKAuthParams @JvmOverloads constructor(val appId: Int, scope: Collection<VKScope> = emptySet()) {
+class VKAuthParams @JvmOverloads constructor(val appId: Int, val redirectUrl: String = DEFAULT_REDIRECT_URL, scope: Collection<VKScope> = emptySet()) {
     private val scope: Set<VKScope>
 
     init {
@@ -41,6 +41,7 @@ class VKAuthParams @JvmOverloads constructor(val appId: Int, scope: Collection<V
         val bundle = Bundle()
         bundle.putInt(VK_APP_ID_KEY, appId)
         bundle.putStringArrayList(VK_APP_SCOPE_KEY, ArrayList(scope.map { it.name }))
+        bundle.putString(VK_APP_REDIRECT_URL_KEY, redirectUrl)
         return bundle
     }
 
@@ -49,6 +50,7 @@ class VKAuthParams @JvmOverloads constructor(val appId: Int, scope: Collection<V
         bundle.putInt(VK_EXTRA_CLIENT_ID, appId)
         bundle.putBoolean(VK_EXTRA_REVOKE, true)
         bundle.putString(VK_EXTRA_SCOPE, scope.joinToString(","))
+        bundle.putString(VK_EXTRA_REDIRECT_URL, redirectUrl)
         return bundle
     }
 
@@ -57,10 +59,14 @@ class VKAuthParams @JvmOverloads constructor(val appId: Int, scope: Collection<V
     companion object {
         private const val VK_APP_ID_KEY = "vk_app_id"
         private const val VK_APP_SCOPE_KEY = "vk_app_scope"
+        private const val VK_APP_REDIRECT_URL_KEY = "vk_app_redirect_url"
 
         private const val VK_EXTRA_CLIENT_ID = "client_id"
         private const val VK_EXTRA_REVOKE = "revoke"
         private const val VK_EXTRA_SCOPE = "scope"
+        private const val VK_EXTRA_REDIRECT_URL = "redirect_url"
+
+        const val DEFAULT_REDIRECT_URL = "https://oauth.vk.com/blank.html"
 
         fun fromBundle(bundle: Bundle?): VKAuthParams? {
             if (bundle == null) {
@@ -68,8 +74,9 @@ class VKAuthParams @JvmOverloads constructor(val appId: Int, scope: Collection<V
             }
             val appId = bundle.getInt(VK_APP_ID_KEY)
             val scope: Collection<VKScope> = bundle.getStringArrayList(VK_APP_SCOPE_KEY)?.map { VKScope.valueOf(it) } ?: emptySet()
+            val redirectUrl = bundle.getString(VK_APP_REDIRECT_URL_KEY, DEFAULT_REDIRECT_URL)
 
-            return VKAuthParams(appId, scope)
+            return VKAuthParams(appId, redirectUrl, scope)
         }
     }
 }
\ No newline at end of file
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/exceptions/VKApiCodes.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/exceptions/VKApiCodes.kt
index 08c2738bd9..e90b516f18 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/exceptions/VKApiCodes.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/exceptions/VKApiCodes.kt
@@ -26,6 +26,7 @@ package com.vk.api.sdk.exceptions
 
 object VKApiCodes {
     const val CODE_COMPOSITE_EXECUTE_ERROR = Int.MIN_VALUE
+    const val CODE_IO_ERROR = -1
     const val CODE_UNKNOWN_ERROR = 1
     const val CODE_APP_DISABLED = 2
     const val CODE_UNKNOWN_METHOD = 3
@@ -83,6 +84,7 @@ object VKApiCodes {
     const val CODE_CHAT_INVITE_MAKE_LINK_DENIED = 919
     const val CODE_MSG_DELETE_FOR_ALL_FAILED = 924
     const val CODE_CHAT_NOT_ADMIN = 925
+    const val CODE_CHAT_MR_ALREADY_SEND = 939
 
     const val CODE_TOO_MANY_CONTACTS_TO_SYNC = 937
 
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/exceptions/VKApiExecutionException.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/exceptions/VKApiExecutionException.kt
index 97bfc86943..e50c962728 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/exceptions/VKApiExecutionException.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/exceptions/VKApiExecutionException.kt
@@ -28,7 +28,7 @@ import android.os.Bundle
 import org.json.JSONObject
 
 /**
- * See [http://vk.com/dev/errors](http://vk.com/dev/errors)
+ * See [https://vk.com/dev/errors](https://vk.com/dev/errors)
  */
 open class VKApiExecutionException
 @JvmOverloads constructor(
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/internal/JsonUtils.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/internal/JsonUtils.kt
index e57b1d7e39..14274322b0 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/internal/JsonUtils.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/internal/JsonUtils.kt
@@ -2,12 +2,21 @@ package com.vk.api.sdk.internal
 
 import android.util.JsonReader
 import android.util.JsonToken
+import android.util.MalformedJsonException
 import java.io.Reader
 import java.io.StringReader
 
 object JsonUtils {
 
     fun containsElement(jsonString: String, name: String): Boolean {
+        try {
+            return containsElementImpl(jsonString, name)
+        } catch (ex: MalformedJsonException) {
+            throw MalformedJsonException("${ex.message}. Json: '$jsonString'")
+        }
+    }
+
+    private fun containsElementImpl(jsonString: String, name: String): Boolean {
         if (jsonString.isEmpty()) {
             return false
         }
@@ -29,4 +38,5 @@ object JsonUtils {
         }
         return false
     }
+
 }
\ No newline at end of file
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/okhttp/LoggingInterceptor.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/okhttp/LoggingInterceptor.kt
index 1ee1fca850..7310211fa4 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/okhttp/LoggingInterceptor.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/okhttp/LoggingInterceptor.kt
@@ -23,9 +23,9 @@
  ******************************************************************************/
 package com.vk.api.sdk.okhttp
 
-import android.support.v4.util.ArrayMap
-import com.vk.api.sdk.utils.log.Logger
+import androidx.collection.ArrayMap
 import com.vk.api.sdk.utils.getValue
+import com.vk.api.sdk.utils.log.Logger
 import com.vk.api.sdk.utils.threadLocal
 import okhttp3.Interceptor
 import okhttp3.Response
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/okhttp/OkHttpExecutor.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/okhttp/OkHttpExecutor.kt
index 3a07f2f126..8e9b1f6396 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/okhttp/OkHttpExecutor.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/okhttp/OkHttpExecutor.kt
@@ -25,11 +25,9 @@ package com.vk.api.sdk.okhttp
 
 import android.net.Uri
 import android.os.Looper
-import android.support.v4.util.LongSparseArray
-import com.vk.api.sdk.OauthHttpUrlPostCall
+import androidx.collection.LongSparseArray
 import com.vk.api.sdk.VKApiProgressListener
 import com.vk.api.sdk.VKOkHttpProvider
-import com.vk.api.sdk.chain.ChainArgs
 import com.vk.api.sdk.exceptions.*
 import com.vk.api.sdk.internal.HttpMultipartEntry
 import com.vk.api.sdk.internal.QueryStringGenerator
@@ -81,27 +79,6 @@ open class OkHttpExecutor(protected val config: OkHttpExecutorConfig) {
         return readResponse(executeRequest(request))
     }
 
-    open fun execute(call: OauthHttpUrlPostCall, chainArgs: ChainArgs?): String? {
-        val url = if (chainArgs != null && chainArgs.hasCaptcha()) {
-            Uri.parse(call.url)
-                    .buildUpon()
-                    .appendQueryParameter(VKApiCodes.EXTRA_CAPTCHA_KEY, chainArgs.captchaKey)
-                    .appendQueryParameter(VKApiCodes.EXTRA_CAPTCHA_SID, chainArgs.captchaSid)
-                    .build()
-                    .toString()
-
-        } else {
-            call.url
-        }
-        val request = Request.Builder()
-                .post(RequestBody.create(null, ""))
-                .cacheControl(CacheControl.FORCE_NETWORK)
-                .url(url)
-                .build()
-
-        return readResponse(executeRequest(request, call.timeoutMs + timeoutDelay))
-    }
-
     @Throws(InterruptedException::class, IOException::class, VKApiException::class)
     fun execute(call: OkHttpPostCall, progressListener: VKApiProgressListener?): String? {
         val body = MultipartBody.Builder()
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/ui/VKWebViewAuthActivity.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/ui/VKWebViewAuthActivity.kt
index e378d2bfae..edcce5602b 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/ui/VKWebViewAuthActivity.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/ui/VKWebViewAuthActivity.kt
@@ -33,13 +33,13 @@ import android.graphics.Bitmap
 import android.net.Uri
 import android.os.Build
 import android.os.Bundle
-import android.support.annotation.RequiresApi
 import android.view.View
 import android.webkit.WebResourceError
 import android.webkit.WebResourceRequest
 import android.webkit.WebView
 import android.webkit.WebViewClient
 import android.widget.ProgressBar
+import androidx.annotation.RequiresApi
 import com.vk.api.sdk.R
 import com.vk.api.sdk.VK
 import com.vk.api.sdk.VKApiValidationHandler
@@ -51,7 +51,7 @@ import com.vk.api.sdk.utils.VKValidationLocker
 /**
  * Activity for showing authorization or validation WebView
  */
-class VKWebViewAuthActivity: Activity() {
+open class VKWebViewAuthActivity: Activity() {
 
     private lateinit var webView: WebView
     private lateinit var progress: ProgressBar
@@ -87,15 +87,28 @@ class VKWebViewAuthActivity: Activity() {
         }
     }
 
+    protected open fun getUrlParams(): Map<String, String> = mapOf(
+            "client_id" to params.appId.toString(),
+            "scope" to params.getScopeString(),
+            "redirect_uri" to params.redirectUrl,
+            "response_type" to "token",
+            "display" to "mobile",
+            "v" to VK.getApiVersion(),
+            "revoke" to "1"
+    )
+
     private fun loadUrl() {
         try {
             val urlToLoad = if (needValidationResult()) intent.getStringExtra(VK_EXTRA_VALIDATION_URL)
-                    else "https://oauth.vk.com/authorize?client_id=${params.appId}" +
-                    "&scope=${params.getScopeString()}" +
-                    "&redirect_uri=$REDIRECT_URL" +
-                    "&display=mobile" +
-                    "&v=${VK.getApiVersion()}" +
-                    "&response_type=token&revoke=1"
+                    else {
+                val uri = Uri.parse("https://oauth.vk.com/authorize").buildUpon()
+                val params = getUrlParams()
+                for ((key, value) in params) {
+                    uri.appendQueryParameter(key, value)
+                }
+                uri.build().toString()
+            }
+
             webView.loadUrl(urlToLoad)
         } catch (e: Exception) {
             setResult(Activity.RESULT_CANCELED)
@@ -129,7 +142,7 @@ class VKWebViewAuthActivity: Activity() {
         }
 
         private fun handleUrl(url: String?): Boolean {
-            if (url == null || !url.startsWith(REDIRECT_URL)) return false
+            if (url == null || !url.startsWith(params.redirectUrl)) return false
 
             val intent = Intent(VK_RESULT_INTENT_NAME)
             val extraData = url.substring(url.indexOf("#") + 1)
@@ -208,7 +221,6 @@ class VKWebViewAuthActivity: Activity() {
     companion object {
         const val VK_EXTRA_AUTH_PARAMS = "vk_auth_params"
         const val VK_RESULT_INTENT_NAME = "com.vk.auth-token"
-        const val REDIRECT_URL = "https://oauth.vk.com/blank.html"
 
         private const val VK_EXTRA_VALIDATION_URL = "vk_validation_url"
 
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/utils/ApiExt.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/utils/ApiExt.kt
index b600585c96..1060e4e277 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/utils/ApiExt.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/utils/ApiExt.kt
@@ -28,7 +28,7 @@ import android.util.MalformedJsonException
 import com.vk.api.sdk.internal.VKErrorUtils
 import java.io.IOException
 import java.io.InterruptedIOException
-import java.net.SocketTimeoutException
+import java.net.*
 
 internal inline fun <T, N : Number> T.applyPos(value: N, block: T.(N) -> Unit): T {
     return if (value.toDouble() > 0) {
@@ -53,4 +53,12 @@ internal fun String.hasSimpleError() = VKErrorUtils.hasSimpleError(this)
 internal fun String.toSimpleError(method: String? = null) = VKErrorUtils.parseSimpleError(this, method)
 internal fun String.toExecuteError(method: String, ignoredErrors: IntArray?) = VKErrorUtils.parseExecuteError(this, method, ignoredErrors)
 
-operator fun <E> android.support.v4.util.LongSparseArray<E>.set(key: Long, value: E) = put(key, value)
+operator fun <E> androidx.collection.LongSparseArray<E>.set(key: Long, value: E) = put(key, value)
+
+fun Throwable.isNetworkException() = this::class in listOf(
+        ConnectException::class,
+        SocketException::class,
+        SocketTimeoutException::class,
+        UnknownHostException::class,
+        ProtocolException::class
+)
\ No newline at end of file
diff --git a/vk-sdk-core/src/main/java/com/vk/api/sdk/utils/VKUtils.kt b/vk-sdk-core/src/main/java/com/vk/api/sdk/utils/VKUtils.kt
index 26b607b556..3f270a0c09 100644
--- a/vk-sdk-core/src/main/java/com/vk/api/sdk/utils/VKUtils.kt
+++ b/vk-sdk-core/src/main/java/com/vk/api/sdk/utils/VKUtils.kt
@@ -22,7 +22,7 @@
  * SOFTWARE.
  ******************************************************************************/
 
-@file:Suppress("DEPRECATION")
+@file:Suppress("DEPRECATION", "unused")
 
 package com.vk.api.sdk.utils