diff --git a/diktat-gradle-plugin/src/functionalTest/kotlin/org/cqfn/diktat/plugin/gradle/DiktatGradlePluginFunctionalTest.kt b/diktat-gradle-plugin/src/functionalTest/kotlin/org/cqfn/diktat/plugin/gradle/DiktatGradlePluginFunctionalTest.kt
index 05d20ee902..d571c31b43 100644
--- a/diktat-gradle-plugin/src/functionalTest/kotlin/org/cqfn/diktat/plugin/gradle/DiktatGradlePluginFunctionalTest.kt
+++ b/diktat-gradle-plugin/src/functionalTest/kotlin/org/cqfn/diktat/plugin/gradle/DiktatGradlePluginFunctionalTest.kt
@@ -4,7 +4,6 @@ import org.cqfn.diktat.plugin.gradle.DiktatGradlePlugin.Companion.DIKTAT_CHECK_T
 import org.gradle.buildinit.plugins.internal.modifiers.BuildInitDsl
 import org.gradle.internal.impldep.org.junit.rules.TemporaryFolder
 import org.gradle.testkit.runner.TaskOutcome
-import org.jetbrains.kotlin.com.intellij.util.ObjectUtils.assertNotNull
 import org.junit.jupiter.api.AfterEach
 import org.junit.jupiter.api.Assertions
 import org.junit.jupiter.api.BeforeEach
@@ -56,7 +55,8 @@ class DiktatGradlePluginFunctionalTest {
         val diktatCheckBuildResult = result.task(":$DIKTAT_CHECK_TASK")
         requireNotNull(diktatCheckBuildResult)
         Assertions.assertEquals(TaskOutcome.FAILED, diktatCheckBuildResult.outcome)
-        val file = assertNotNull(testProjectDir.root.walkTopDown().filter { it.name == "test.txt" }.first())
+        val file = testProjectDir.root.walkTopDown().filter { it.name == "test.txt" }.first()
+        Assertions.assertNotNull(file)
         Assertions.assertTrue(
                 file.readLines().any { it.contains("[FILE_NAME_MATCH_CLASS]") }
         )
diff --git a/diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/generation/Generation.kt b/diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/generation/Generation.kt
index 65a54a33e5..62282fb6c9 100644
--- a/diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/generation/Generation.kt
+++ b/diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/generation/Generation.kt
@@ -16,6 +16,9 @@ import com.squareup.kotlinpoet.TypeSpec
 
 import java.io.File
 
+import kotlin.io.path.ExperimentalPathApi
+import kotlin.io.path.createTempFile
+
 /**
  * The comment that will be added to the generated sources file.
  */
@@ -56,13 +59,14 @@ private fun generateWarningNames() {
     kotlinFile.writeTo(File("diktat-rules/src/main/kotlin"))  // fixme: need to add it to pom
 }
 
+@OptIn(ExperimentalPathApi::class)
 private fun validateYear() {
     val files = File("diktat-rules/src/test/resources/test/paragraph2/header")
     files
         .listFiles()
         .filterNot { it.name.contains("CopyrightDifferentYearTest.kt") }
         .forEach { file ->
-            val tempFile = createTempFile()
+            val tempFile = createTempFile().toFile()
             tempFile.printWriter().use { writer ->
                 file.forEachLine { line ->
                     writer.println(when {
diff --git a/diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/rules/chapter3/EmptyBlock.kt b/diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/rules/chapter3/EmptyBlock.kt
index 8a1dd69960..19f4973aa5 100644
--- a/diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/rules/chapter3/EmptyBlock.kt
+++ b/diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/rules/chapter3/EmptyBlock.kt
@@ -9,14 +9,10 @@ import org.cqfn.diktat.ruleset.utils.*
 
 import com.pinterest.ktlint.core.ast.ElementType
 import com.pinterest.ktlint.core.ast.ElementType.CALL_EXPRESSION
-import com.pinterest.ktlint.core.ast.ElementType.DOT_QUALIFIED_EXPRESSION
-import com.pinterest.ktlint.core.ast.ElementType.FILE
 import com.pinterest.ktlint.core.ast.ElementType.FUNCTION_LITERAL
 import com.pinterest.ktlint.core.ast.ElementType.IDENTIFIER
 import com.pinterest.ktlint.core.ast.ElementType.LAMBDA_EXPRESSION
-import com.pinterest.ktlint.core.ast.ElementType.LPAR
 import com.pinterest.ktlint.core.ast.ElementType.RBRACE
-import com.pinterest.ktlint.core.ast.ElementType.VALUE_ARGUMENT
 import com.pinterest.ktlint.core.ast.ElementType.VALUE_ARGUMENT_LIST
 import com.pinterest.ktlint.core.ast.ElementType.VALUE_PARAMETER
 import com.pinterest.ktlint.core.ast.ElementType.WHITE_SPACE
diff --git a/diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/smoke/DiktatSmokeTest.kt b/diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/smoke/DiktatSmokeTest.kt
index 1bd5a84e29..5e852122e6 100644
--- a/diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/smoke/DiktatSmokeTest.kt
+++ b/diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/smoke/DiktatSmokeTest.kt
@@ -27,7 +27,8 @@ import org.junit.jupiter.api.Tag
 import org.junit.jupiter.api.Test
 
 import java.time.LocalDate
-
+import kotlin.io.path.ExperimentalPathApi
+import kotlin.io.path.createTempFile
 import kotlinx.serialization.encodeToString
 
 typealias ruleToConfig = Map<String, Map<String, String>>
@@ -37,6 +38,7 @@ typealias ruleToConfig = Map<String, Map<String, String>>
  * Note: ktlint uses initial text from a file to calculate line and column from offset. Because of that line/col of unfixed errors
  * may change after some changes to text or other rules.
  */
+@OptIn(ExperimentalPathApi::class)
 class DiktatSmokeTest : FixTestBase("test/smoke/src/main/kotlin",
     { DiktatRuleSetProvider(configFilePath) },
     { lintError, _ -> unfixedLintErrors.add(lintError) },
@@ -59,7 +61,7 @@ class DiktatSmokeTest : FixTestBase("test/smoke/src/main/kotlin",
                     rulesConfig.add(RulesConfig(warning, enabled = true, configuration = configuration))
                 }
             }
-        createTempFile()
+        createTempFile().toFile()
             .also {
                 configFilePath = it.absolutePath
             }
diff --git a/diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/smoke/RulesConfigValidationTest.kt b/diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/smoke/RulesConfigValidationTest.kt
index 39ec8c226b..e5de33f855 100644
--- a/diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/smoke/RulesConfigValidationTest.kt
+++ b/diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/smoke/RulesConfigValidationTest.kt
@@ -12,13 +12,16 @@ import org.junit.jupiter.api.assertThrows
 
 import java.io.File
 import java.lang.IllegalArgumentException
+import kotlin.io.path.ExperimentalPathApi
+import kotlin.io.path.createTempFile
 
+@OptIn(ExperimentalPathApi::class)
 class RulesConfigValidationTest {
     private lateinit var file: File
 
     @BeforeEach
     fun setUp() {
-        file = createTempFile()
+        file = createTempFile().toFile()
     }
 
     @AfterEach
diff --git a/pom.xml b/pom.xml
index b0b3fc3879..6179734f57 100644
--- a/pom.xml
+++ b/pom.xml
@@ -81,6 +81,11 @@
                 <artifactId>kotlinpoet</artifactId>
                 <version>${kotlinpoet.version}</version>
             </dependency>
+            <dependency>
+                <groupId>org.jetbrains.kotlin</groupId>
+                <artifactId>kotlin-stdlib</artifactId>
+                <version>${kotlin.version}</version>
+            </dependency>
             <dependency>
                 <groupId>org.jetbrains.kotlin</groupId>
                 <artifactId>kotlin-stdlib-jdk8</artifactId>